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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on VP2(NO4)2 by Materials Project

VP2(NO4)2 crystallizes in the tetragonal P4bm space group. The structure is two-dimensional and consists of one VP2(NO4)2 sheet oriented in the (0, 0, 1) direction. V4+ is bonded to five O2- atoms to form distorted VO5 trigonal bipyramids that share corners with four equivalent PO4 tetrahedra. There is one shorter (1.61 Å) and four longer (2.03 Å) V–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with two equivalent VO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.50–1.66 Å. N1+ is bonded in a single-bond geometry to one O2- atom. The N–O bond length is 1.34 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the second O2- site, O2- is bonded in a linear geometry to two equivalent P5+ atoms. In the third O2- site, O2- is bonded in a single-bond geometry to one V4+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one N1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VP2(HO)6 by Materials Project

VP2(HO)6 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. V2+ is bonded to six O2- atoms to form distorted VO6 octahedra that share corners with four equivalent PH2O2 tetrahedra. There are a spread of V–O bond distances ranging from 1.63–2.33 Å. P5+ is bonded to two H and two O2- atoms to form distorted PH2O2 tetrahedra that share corners with two equivalent VO6 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. Both P–H bond lengths are 1.41 Å. There is one shorter (1.53 Å) and one longer (1.54 Å) P–O bond length. There are three inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (0.98 Å) and one longer (1.97 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one P5+ atom. In the third H site, H is bonded in a single-bond geometry to one P5+ atom. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one V2+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one V2+, one P5+, and one H atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to one V2+ and two equivalent H atoms. In the fourth O2- site, O2- is bonded in a single-bond geometry to one V2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VP2 by Materials Project

P2V crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. V5+ is bonded in a 8-coordinate geometry to eight P+2.50- atoms. There are a spread of V–P bond distances ranging from 2.43–2.49 Å. There are two inequivalent P+2.50- sites. In the first P+2.50- site, P+2.50- is bonded in a 4-coordinate geometry to three equivalent V5+ and three equivalent P+2.50- atoms. There are one shorter (2.23 Å) and two longer (2.58 Å) P–P bond lengths. In the second P+2.50- site, P+2.50- is bonded in a 5-coordinate geometry to five equivalent V5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Altered Expression of Two Small Secreted Proteins (ssp4 and ssp6) Affects the Degradation of a Natural Lignocellulosic Substrate by Pleurotus ostreatus

Pleurotus ostreatus is a white-rot fungus that can degrade lignin in a preferential manner using a variety of extracellular enzymes, including manganese and versatile peroxidases (encoded by the vp1-3 and mnp1-6 genes, respectively). This fungus also secretes a family of structurally related small secreted proteins (SSPs) encoded by the ssp1-6 genes. Using RNA sequencing (RNA-seq), we determined that ssp4 and ssp6 are the predominant members of this gene family that were expressed by P. ostreatus during the first three weeks of growth on wheat straw. Downregulation of ssp4 in a strain harboring an ssp RNAi construct (KDssp1) was then confirmed, which, along with an increase in ssp6 transcript levels, coincided with reduced lignin degradation and the downregulation of vp2 and mnp1. In contrast, we observed an increase in the expression of genes related to pectin and side-chain hemicellulose degradation, which was accompanied by an increase in extracellular pectin-degrading capacity. Genome-wide comparisons between the KDssp1 and the wild-type strains demonstrated that ssp silencing conferred accumulated changes in gene expression at the advanced cultivation stages in an adaptive rather than an inductive mode of transcriptional response. Based on co-expression networking, crucial gene modules were identified and linked to the ssp knockdown genotype at different cultivation times. Based on these data, as well as previous studies, we propose that P. ostreatus SSPs have potential roles in modulating the lignocellulolytic and pectinolytic systems, as well as a variety of fundamental biological processes related to fungal growth and development.

59 BASIC BIOLOGICAL SCIENCES↗