Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ATP”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3

ATP- and Polyphosphate-Dependent Glucokinases from Aerobic Methanotrophs

The genes encoding adenosine triphosphate (ATP)- and polyphosphate (polyP)-dependent glucokinases (Glk) were identified in the aerobic obligate methanotroph Methylomonas sp. 12. The recombinant proteins were obtained by the heterologous expression of the glk genes in Esherichia coli. ATP-Glk behaved as a multimeric protein consisting of di-, tri-, tetra-, penta- and hexamers with a subunit molecular mass of 35.5 kDa. ATP-Glk phosphorylated glucose and glucosamine using ATP (100% activity), uridine triphosphate (UTP) (85%) or guanosine triphosphate (GTP) (71%) as a phosphoryl donor and exhibited the highest activity in the presence of 5 mM Mg 2+ at pH 7.5 and 65 °C but was fully inactivated after a short-term incubation at this temperature. According to a gel filtration in the presence of polyP, the polyP-dependent Glk was a dimeric protein (2 × 28 kDa). PolyP-Glk phosphorylated glucose, mannose, 2-deoxy-D-glucose, glucosamine and N-acetylglucosamine using polyP as the phosphoryl donor but not using nucleoside triphosphates. The K m values of ATP-Glk for glucose and ATP were about 78 μM, and the K m values of polyP-Glk for glucose and polyP (n=45) were 450 and 21 μM, respectively. The genomic analysis of methanotrophs showed that ATP-dependent glucokinase is present in all sequenced methanotrophs, with the exception of the genera Methylosinus and Methylocystis, whereas polyP-Glks were found in all species of the genus Methylomonas and in Methylomarinum vadi only. This work presents the first characterization of polyphosphate specific glucokinase in a methanotrophic bacterium.

59 BASIC BIOLOGICAL SCIENCES↗

Evaluating the contribution of plant metabolic pathways in the light to the ATP:NADPH demand using a meta-analysis of isotopically non-stationary metabolic flux analyses

Abstract Balancing the ATP: NADPH demand from plant metabolism with supply from photosynthesis is essential for preventing photodamage and operating efficiently, so understanding its drivers is important for integrating metabolism with the light reactions of photosynthesis and for bioengineering efforts that may radically change this demand. It is often assumed that the C3 cycle and photorespiration consume the largest amount of ATP and reductant in illuminated leaves and as a result mostly determine the ATP: NADPH demand. However, the quantitative extent to which other energy consuming metabolic processes contribute in large ways to overall ATP: NADPH demand remains unknown. Here, we used the metabolic flux networks of numerous recently published isotopically non-stationary metabolic flux analyses (INST-MFA) to evaluate flux through the C3 cycle, photorespiration, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and starch/sucrose synthesis and characterize broad trends in the demand of energy across different pathways and compartments as well as in the overall ATP:NADPH demand. These data sets include a variety of species including Arabidopsis thaliana , Nicotiana tabacum , and Camelina sativa as well as varying environmental factors including high/low light, day length, and photorespiratory levels. Examining these datasets in aggregate reveals that ultimately the bulk of the energy flux occurred in the C3 cycle and photorespiration, however, the energy demand from these pathways did not determine the ATP: NADPH demand alone. Instead, a notable contribution was revealed from starch and sucrose synthesis which might counterbalance photorespiratory demand and result in fewer adjustments in mechanisms which balance the ATP deficit.

59 BASIC BIOLOGICAL SCIENCES↗

Role of inositol 1,4,5-trisphosphate receptor type 1 in ATP-induced nuclear Ca2+ signal and hypertrophy in atrial myocytes

Highlights: • IP{sub 3} receptor type 1 (IP{sub 3}R1) are expressed in atrial cell perinucleus. • IP{sub 3}R1 mediates ATP-induced sustained nuclear Ca{sup 2+} increase in HL-1 atrial cells. • IP{sub 3}R1 contributes to higher sensitivity of nuclear release sites upon IP{sub 3} increase. • Larger Ca{sup 2+} content in perinuclear store of atrial cells involves IP{sub 3}R1. • IP{sub 3}R1 signaling may play a role in ATP-induced atrial cell hypertrophy. Inositol 1,4,5-trisphosphate receptor type 1 (IP{sub 3}R1) is expressed in atrial muscle, but not in ventricle, and they are abundant in the perinucleus. We investigated the role of IP{sub 3}R1 in the regulations of local Ca{sup 2+} signal and cell size in HL-1 atrial myocytes under stimulation by IP{sub 3}-generating chemical messenger, ATP. Assessment of nuclear and cytosolic Ca{sup 2+} signal using confocal Ca{sup 2+} imaging revealed that IP{sub 3} generation by ATP (1 mM) induced monophasic nuclear Ca{sup 2+} increase, followed by cytosolic Ca{sup 2+} oscillation. Genetic knock-down (KD) of IP{sub 3}R1 eliminated the monophasic nuclear Ca{sup 2+} signal and slowed the cytosolic Ca{sup 2+} oscillation upon ATP exposure. Prolonged application of ATP as well as other known hypertrophic agonists (endothelin-1 and phenylephrine) increased cell size in wild-type cells, but not in IP{sub 3}R1 KD cells. Our data indicate that IP{sub 3}R1 mediates sustained elevation in nuclear Ca{sup 2+} level and facilitates cytosolic Ca{sup 2+} oscillation upon external ATP increase, and further suggests possible role of nuclear IP{sub 3}R1 in atrial hypertrophy.

60 APPLIED LIFE SCIENCES↗

Crystallographic and kinetic analyses of human IPMK reveal disordered domains modulate ATP binding and kinase activity

Inositol polyphosphate multikinase (IPMK) is a member of the IPK-superfamily of kinases, catalyzing phosphorylation of several soluble inositols and the signaling phospholipid PI(4,5)P 2 (PIP 2 ). IPMK also has critical non-catalytic roles in p53, mTOR/Raptor, TRAF6 and AMPK signaling mediated partly by two disordered domains. Although IPMK non-catalytic functions are well established, it is less clear if the disordered domains are important for IPMK kinase activity or ATP binding. Here, kinetic and structural analyses of an engineered human IPMK lacking all disordered domains (ΔIPMK) are presented. Although the K M for PIP 2 is identical between ΔIPMK and wild type, ΔIPMK has a 1.8-fold increase in k cat for PIP 2 , indicating the native IPMK disordered domains decrease IPMK activity in vitro . The 2.5 Å crystal structure of ΔIPMK is reported, confirming the conserved ATP-grasp fold. A comparison with other IPK-superfamily structures revealed a putative “ATP-clamp” in the disordered N-terminus, we predicted would stabilize ATP binding. Consistent with this observation, removal of the ATP clamp sequence increases the K M for ATP 4.9-fold, indicating the N-terminus enhances ATP binding to IPMK. Together, these structural and kinetic studies suggest in addition to mediating protein-protein interactions, the disordered domains of IPMK impart modulatory capacity to IPMK kinase activity through multiple kinetic mechanisms.

59 BASIC BIOLOGICAL SCIENCES↗

Mitochondrial Hsp90 is a ligand-activated molecular chaperone coupling ATP binding to dimer closure through a coiled-coil intermediate

Heat-shock protein of 90 kDa (Hsp90) is an essential molecular chaperone that adopts different 3D structures associated with distinct nucleotide states: a wide-open, V-shaped dimer in the apo state and a twisted, N-terminally closed dimer with ATP. Although the N domain is known to mediate ATP binding, how Hsp90 senses the bound nucleotide and facilitates dimer closure remains unclear. In this paper we present atomic structures of human mitochondrial Hsp90 N (TRAP1 N ) and a composite model of intact TRAP1 revealing a previously unobserved coiled-coil dimer conformation that may precede dimer closure and is conserved in intact TRAP1 in solution. Our structure suggests that TRAP1 normally exists in an autoinhibited state with the ATP lid bound to the nucleotide-binding pocket. ATP binding displaces the ATP lid that signals the cis-bound ATP status to the neighboring subunit in a highly cooperative manner compatible with the coiled-coil intermediate state. We propose that TRAP1 is a ligand-activated molecular chaperone, which couples ATP binding to dramatic changes in local structure required for protein folding.

59 BASIC BIOLOGICAL SCIENCES↗

Ca{sup 2+} influx and ATP release mediated by mechanical stretch in human lung fibroblasts

Highlights: • Uniaxial stretching activates Ca{sup 2+} signaling in human lung fibroblasts. • Stretch-induced intracellular Ca{sup 2+} elevation is mainly via Ca{sup 2+} influx. • Mechanical strain enhances ATP release from fibroblasts. • Stretch-induced Ca{sup 2+} influx is not mediated by released ATP or actin cytoskeleton. - Abstract: One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10–30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca{sup 2+}]{sub i} transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca{sup 2+}]{sub i}. The stretch-induced [Ca{sup 2+}]{sub i} elevation was attenuated in Ca{sup 2+}-free solution. In contrast, the increase of [Ca{sup 2+}]{sub i} by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd{sup 3+}, ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca{sup 2+}]{sub i} elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca{sup 2+} influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP.

60 APPLIED LIFE SCIENCES↗

Sildenafil protects neuronal cells from mitochondrial toxicity induced by β-amyloid peptide via ATP-sensitive K+ channels

To understand the molecular mechanisms underlying the beneficial effects of sildenafil in animal models of neurological disorders, we investigated the effects of sildenafil on the mitochondrial toxicity induced by β-amyloid (Aβ) peptide. Treatment of HT-22 hippocampal neuronal cells with Aβ{sub 25∼35} results in increased mitochondrial Ca{sup 2+} load, which is subsequently suppressed by sildenafil as well as by diazoxide, a selective opener of the ATP-sensitive K{sup +} channels (K{sub ATP}). However, the suppressive effects of sildenafil and diazoxide are significantly attenuated by 5-hydroxydecanoic acid (5-HD), a K{sub ATP} inhibitor. The increased mitochondrial Ca{sup 2+} overload is accompanied by decrease in the intracellular ATP concentration, increase in intracellular ROS generation, occurrence of mitochondrial permeability transition, and activation of caspase-9 and cell death. Exposure to sildenafil inhibited the mitochondria-associated changes and cell death induced by Aβ. However, the inhibitory effects of sildenafil are abolished or weakened in the presence of 5-HD, suggesting that opening of the mitochondrial K{sub ATP} is required for sildenafil to exert these effects. Taken together, these results indicate that at the mitochondrial levels, sildenafil plays a protective role towards neuronal cell in an environment rich in Aβ, and exerts its effects via the mitochondrial K{sub ATP} channels-dependent mechanisms.

60 APPLIED LIFE SCIENCES↗

Profilin facilitates PKCε activation by accelerating ATP supply

Higghlights• Profilin associates with activated PKCε. • Profilin does not activate PKCε directly. • Profilin facilitates PKCε activation by accelerating ATP supply. Profilin catalyzes the exchange of actin-bound ADP to ATP. The present study investigated the role of profilin in PKCε activation. Profilin associated with PKCε in differentiated PC-12 cells under the basal conditions, which was inhibited by the PKC inhibitor GF109203X. The selective PKCε activator DCP-LA markedly increased the association, which was clearly prevented by GF109203X. The basal PKC activity in PC-12 cells was attenuated by knocking-down profilin, while the basal activities of PKA and CaMKII were not affected. DCP-LA enhanced the PKC activity to approximately 3.5 folds of the basal levels, and the effect was suppressed by knocking-down profilin. In the cell-free system, PKCε was not activated by profilin alone. DCP-LA activated PKCε in an ATP concentration (2–500 μM)-dependent manner, and addition of profilin shifted the ATP concentration/DCP-LA-induced PKCε activity relation curve to the left (the direction of lower ATP concentrations). Taken together, the results of the present study indicate that profilin binds to activated PKCε and facilitates PKCε activation by accelerating ATP supply to PKCε.

60 APPLIED LIFE SCIENCES↗

Dimers of mitochondrial ATP synthase induce membrane curvature and self-assemble into rows

Mitochondrial ATP synthases form dimers, which assemble into long ribbons at the rims of the inner membrane cristae. We reconstituted detergent-purified mitochondrial ATP synthase dimers from the green algae Polytomella sp. and the yeast Yarrowia lipolytica into liposomes and examined them by electron cryotomography. Tomographic volumes revealed that ATP synthase dimers from both species self-assemble into rows and bend the lipid bilayer locally. The dimer rows and the induced degree of membrane curvature closely resemble those in the inner membrane cristae. Monomers of mitochondrial ATP synthase reconstituted into liposomes do not bend membrane visibly and do not form rows. No specific lipids or proteins other than ATP synthase dimers are required for row formation and membrane remodelling. Long rows of ATP synthase dimers are a conserved feature of mitochondrial inner membranes. They are required for cristae formation and a main factor in mitochondrial morphogenesis.

59 BASIC BIOLOGICAL SCIENCES↗

Vascular K ATP channel structural dynamics reveal regulatory mechanism by Mg-nucleotides

Vascular tone is dependent on smooth muscle K ATP channels comprising pore-forming Kir6.1 and regulatory SUR2B subunits, in which mutations cause Cantú syndrome. Unique among K ATP isoforms, they lack spontaneous activity and require Mg-nucleotides for activation. Structural mechanisms underlying these properties are unknown. Here, we determined cryogenic electron microscopy structures of vascular K ATP channels bound to inhibitory ATP and glibenclamide, which differ informatively from similarly determined pancreatic K ATP channel isoform (Kir6.2/SUR1). Unlike SUR1, SUR2B subunits adopt distinct rotational “propeller” and “quatrefoil” geometries surrounding their Kir6.1 core. The glutamate/aspartate-rich linker connecting the two halves of the SUR-ABC core is observed in a quatrefoil-like conformation. Molecular dynamics simulations reveal MgADP-dependent dynamic tripartite interactions between this linker, SUR2B, and Kir6.1. The structures captured implicate a progression of intermediate states between MgADP-free inactivated, and MgADP-bound activated conformations wherein the glutamate/aspartate-rich linker participates as mobile autoinhibitory domain, suggesting a conformational pathway toward K ATP channel activation.

59 BASIC BIOLOGICAL SCIENCES↗

Dephosphorylation of the Core Clock Protein KaiC in the Cyanobacterial KaiABC Circadian Oscillator Proceeds via an ATP Synthase Mechanism

The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro from three proteins, KaiA, KaiB, and KaiC in the presence of ATP, to tick in a temperature-compensated manner. KaiC, the central cog of this oscillator, forms a homohexamer with 12 ATP molecules bound between its N- and C-terminal domains and exhibits unusual properties. Both the N-terminal (CI) and C-terminal (CII) domains harbor ATPase activity, and the subunit interfaces between CII domains are the sites of autokinase and autophosphatase activities. Hydrolysis of ATP correlates with phosphorylation at threonine and serine sites across subunits in an orchestrated manner, such that first T432 and then S431 are phosphorylated, followed by dephosphorylation of these residues in the same order. Although structural work has provided insight into the mechanisms of ATPase and kinase, the location and mechanism of the phosphatase have remained enigmatic. From the available experimental data based on a range of approaches, including KaiC crystal structures and small-angle X-ray scattering models, metal ion dependence, site-directed mutagenesis (i.e., E318, the general base), and measurements of the associated clock periods, phosphorylation patterns, and dephosphorylation courses as well as a lack of sequence motifs in KaiC that are typically associated with known phosphatases, we hypothesized that KaiCII makes use of the same active site for phosphorylation and dephosphorlyation. We observed that wild-type KaiC (wt-KaiC) exhibits an ATP synthase activity that is significantly reduced in the T432A/S431A mutant. We interpret the first observation as evidence that KaiCII is a phosphotransferase instead of a phosphatase and the second that the enzyme is capable of generating ATP, both from ADP and P{sub i} (in a reversal of the ATPase reaction) and from ADP and P-T432/P-S431 (dephosphorylation). This new concept regarding the mechanism of dephosphorylation is also supported by the strikingly similar makeups of the active sites at the interfaces between {alpha}/{beta} heterodimers of F1-ATPase and between monomeric subunits in the KaiCII hexamer. Several KaiCII residues play a critical role in the relative activities of kinase and ATP synthase, among them R385, which stabilizes the compact form and helps kinase action reach a plateau, and T426, a short-lived phosphorylation site that promotes and affects the order of dephosphorylation.

59 BASIC BIOLOGICAL SCIENCES↗

CryoEM reveals the stochastic nature of individual ATP binding events in a group II chaperonin

Chaperonins are homo- or hetero-oligomeric complexes that use ATP binding and hydrolysis to facilitate protein folding. ATP hydrolysis exhibits both positive and negative cooperativity. The mechanism by which chaperonins coordinate ATP utilization in their multiple subunits remains unclear. Here we use cryoEM to study ATP binding in the homo-oligomeric archaeal chaperonin from Methanococcus maripaludis (MmCpn), consisting of two stacked rings composed of eight identical subunits each. Using a series of image classification steps, we obtained different structural snapshots of individual chaperonins undergoing the nucleotide binding process. We identified nucleotide-bound and free states of individual subunits in each chaperonin, allowing us to determine the ATP occupancy state of each MmCpn particle. We observe distinctive tertiary and quaternary structures reflecting variations in nucleotide occupancy and subunit conformations in each chaperonin complex. Detailed analysis of the nucleotide distribution in each MmCpn complex indicates that individual ATP binding events occur in a statistically random manner for MmCpn, both within and across the rings. Our findings illustrate the power of cryoEM to characterize a biochemical property of multi-subunit ligand binding cooperativity at the individual particle level.

59 BASIC BIOLOGICAL SCIENCES↗

Expanding the use of ethanol as a feedstock for cell-free synthetic biochemistry by implementing acetyl-CoA and ATP generating pathways

Abstract Ethanol is a widely available carbon compound that can be increasingly produced with a net negative carbon balance. Carbon-negative ethanol might therefore provide a feedstock for building a wider range of sustainable chemicals. Here we show how ethanol can be converted with a cell free system into acetyl-CoA, a central precursor for myriad biochemicals, and how we can use the energy stored in ethanol to generate ATP, another key molecule important for powering biochemical pathways. The ATP generator produces acetone as a value-added side product. Our ATP generator reached titers of 27 ± 6 mM ATP and 59 ± 15 mM acetone with maximum ATP synthesis rate of 2.8 ± 0.6 mM/h and acetone of 7.8 ± 0.8 mM/h. We illustrated how the ATP generating module can power cell-free biochemical pathways by converting mevalonate into isoprenol at a titer of 12.5 ± 0.8 mM and a maximum productivity of 1.0 ± 0.05 mM/h. These proof-of-principle demonstrations may ultimately find their way to the manufacture of diverse chemicals from ethanol and other simple carbon compounds.

59 BASIC BIOLOGICAL SCIENCES↗

The role of photorespiration in preventing feedback regulation via ATP synthase in Nicotiana tabacum

Abstract Photorespiration consumes substantial amounts of energy in the forms of adenosine triphosphate (ATP) and reductant making the pathway an important component in leaf energetics. Because of this high reductant demand, photorespiration is proposed to act as a photoprotective electron sink. However, photorespiration consumes more ATP relative to reductant than the C3 cycle meaning increased flux disproportionally increases ATP demand relative to reductant. Here we explore how energetic consumption from photorespiration impacts the flexibility of the light reactions in nicotiana tabacum . Specifically, we demonstrate that decreased photosynthetic efficiency (ϕ II ) at low photorespiratory flux was related to feedback regulation at the chloroplast ATP synthase. Additionally, decreased ϕ II at high photorespiratory flux resulted in the accumulation of photoinhibition at photosystem II centers. These results are contrary to the proposed role of photorespiration as a photoprotective electron sink. Instead, our results suggest a novel role of ATP consumption from photorespiration in maintaining ATP synthase activity, with implications for maintaining energy balance and preventing photodamage that will be critical for plant engineering strategies.

Plant Sciences↗

Cristae architecture is determined by an interplay of the MICOS complex and the F 1 F o ATP synthase via Mic27 and Mic10

The inner boundary and the cristae membrane are connected by pore-like structures termed crista junctions (CJs). The MICOS complex is required for CJ formation and enriched at CJs. Here, we address the roles of the MICOS subunits Mic27 and Mic10. We observe a positive genetic interaction between Mic27 and Mic60 and deletion of Mic27 results in impaired formation of CJs and altered cristae membrane curvature. Mic27 acts in an antagonistic manner to Mic60 as it promotes oligomerization of the F1FO-ATP synthase and partially restores CJ formation in cells lacking Mic60. Mic10 impairs oligomerization of the F1FO-ATP synthase similar to Mic60. Applying complexome profiling, we observed that deletion of Mic27 destabilizes the MICOS complex but does not impair formation of a high molecular weight Mic10 subcomplex. Moreover, this Mic10 subcomplex comigrates with the dimeric F1FO-ATP synthase in a Mic27-independent manner. Further, we observed a chemical crosslink of Mic10 to Mic27 and of Mic10 to the F1FO-ATP synthase subunit e. We corroborate the physical interaction of the MICOS complex and the F1FO-ATP synthase. We propose a model in which part of the F1FO-ATP synthase is linked to the MICOS complex via Mic10 and Mic27 and by that is regulating CJ formation.

59 BASIC BIOLOGICAL SCIENCES↗

The effect of growth phase and medium on the use of the firefly adenosine triphosphate (ATP) assay for the quantitation of bacteria

Luciferase assay for adenosine triphosphate (ATP) was used as a rapid method to determine the number of bacteria in a urine sample after nonbacterial components were removed. Accurate cellular ATP values, determined when bacteria were grown in an environment similar to that in which they were found, were necessary for the calculation of bacterial titer in urine. Cellular ATP values vary depending on the extraction method, the cell growth phase, and cell growth conditions. ATP per cell values of stationary E. coli grown in urine were two times greater than ATP per cell values of cells grown in trypticase soy broth. Glucose and urea were examined as possible components responsible for the cellular ATP variation.

Bush, V. N.↗

Tracking protons from respiratory chain complexes to ATP synthase c-subunit: The critical role of serine and threonine residues

F{sub 1}F{sub o}-ATP synthase is a multisubunit enzyme responsible for the synthesis of ATP. Among its multiple subunits (8 in E. coli, 17 in yeast S. cerevisiae, 16 in vertebrates), two subunits a and c are known to play a central role controlling the H{sup +} flow through the inner mitochondrial membrane which allows the subsequent synthesis of ATP, but the pathway followed by H{sup +} within the two proteins is still a matter of debate. In fact, even though the structure of ATP synthase is now well defined, the molecular mechanisms determining the function of both F{sub 1} and F{sub O} domains are still largely unknown. In this study, we propose a pathway for proton migration along the ATP synthase by hydrogen-bonded chain mechanism, with a key role of serine and threonine residues, by X-ray diffraction data on the subunit a of E. coli Fo.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Metallurgical and mechanical characterization of ATP-5 aluminum alloys for minimizing machining distortion

ATP-5 aluminum alloy was considered as an alternative to 6061-T651 aluminum alloy to minimize machining distortion. ATP-5 is a proprietary cast alloy that is compositionally similar to 5083 aluminum and is purported to have excellent machinability, stability, and corrosion response. Dimensional stability tests, mechanical testing, chemical analysis, microstructural analysis, and fractography were completed to understand the metallurgy of the ATP-5 alloy and assess its potential as a 6061-T651 alloy alternative. Ultimately, the ATP-5 was found to retain dimensional stability issues, albeit to a lesser extent, relative to the 6061-T651 alloy. Combined with the residual cast structure observed microstructurally and lot-to-lot mechanical property variation, the alloy was deemed not suitable for a structural application. Alternative uses of ATP-5 include tooling, molds, vacuum chucks, fixtures, and jigs, where the material can shine in non-load bearing applications with a need for dimensional control and machinability.

36 MATERIALS SCIENCE↗