Structural basis of TRAPPIII‐mediated Rab1 activation

The GTPase Rab1 is a master regulator of the early secretory pathway and is critical for autophagy. Rab1 activation is controlled by its guanine nucleotide exchange factor, the multisubunit TRAPPIII complex. Here, we report the 3.7 Å cryo‐EM structure of the Saccharomyces cerevisiae TRAPPIII complex bound to its substrate Rab1/Ypt1. The structure reveals the binding site for the Rab1/Ypt1 hypervariable domain, leading to a model for how the complex interacts with membranes during the activation reaction. We determined that stable membrane binding by the TRAPPIII complex is required for robust activation of Rab1/Ypt1 in vitro and in vivo, and is mediated by a conserved amphipathic α‐helix within the regulatory Trs85 subunit. Our results show that the Trs85 subunit serves as a membrane anchor, via its amphipathic helix, for the entire TRAPPIII complex. These findings provide a structural understanding of Rab activation on organelle and vesicle membranes

Structural basis of TRAPPIII‐mediated Rab1 activation

The GTPase Rab1 is a master regulator of the early secretory pathway and is critical for autophagy. Rab1 activation is controlled by its guanine nucleotide exchange factor, the multisubunit TRAPPIII complex. Here, we report the 3.7 Å cryo‐EM structure of the Saccharomyces cerevisiae TRAPPIII complex bound to its substrate Rab1/Ypt1. The structure reveals the binding site for the Rab1/Ypt1 hypervariable domain, leading to a model for how the complex interacts with membranes during the activation reaction. We determined that stable membrane binding by the TRAPPIII complex is required for robust activation of Rab1/Ypt1 in vitro and in vivo, and is mediated by a conserved amphipathic α‐helix within the regulatory Trs85 subunit. Our results show that the Trs85 subunit serves as a membrane anchor, via its amphipathic helix, for the entire TRAPPIII complex. These findings provide a structural understanding of Rab activation on organelle and vesicle membranes

Selection of accessions from minicore to improve disease resistance in groundnut

A mini core subset of world germplasm comprising 188 accessions was evaluated for late leaf spot, rust and seed colonization by A. flavus. Accessions highly resistant to late leaf spot (ICG 2857, ICG 8760, ICG 12625, ICG 13787, ICG 12672, ICG 14475 and ICG 11426), rust (ICG 4746, ICG 6706, ICG 11088 and ICG 11426) and A. flavus (ICG 14985, ICG 6025, ICG 3673, ICG 12625, ICG 13787 and ICG 8760) were identified. Some accessions (ICG 12625, ICG 13787, ICG 11426 and ICG 8760) combined resistance to at least two diseases. The identified accessions along with three popular cultivars (GPBD 4, TAG 24 and JL 24) were subjected to RAPD assay using twenty primers to assess molecular diversity. The genetic similarity (Sij) ranged from 0.64 to 0.92. Accessions ICG 6706, 14475 and 8760 were more diverse with the popular varieties. The information generated in this study will be of great value to plant breeders in their effort to develop varieties resistant to fungal diseases through hybridization

Reliable identification of protein-protein interactions by crosslinking mass spectrometry

Protein-protein interactions govern most cellular pathways and processes, and multiple technologies have emerged to systematically map them. Assessing the error of interaction networks has been a challenge. Crosslinking mass spectrometry is currently widening its scope from structural analyses of purified multi-protein complexes towards systems-wide analyses of protein-protein interactions (PPIs). Using a carefully controlled large-scale analysis of Escherichia coli cell lysate, we demonstrate that false-discovery rates (FDR) for PPIs identified by crosslinking mass spectrometry can be reliably estimated. We present an interaction network comprising 590 PPIs at 1% decoy-based PPI-FDR. The structural information included in this network localises the binding site of the hitherto uncharacterised protein YacL to near the DNA exit tunnel on the RNA polymerase.TU Berlin, Open-Access-Mittel – 2021DFG, 390540038, EXC 2008: Unifying Systems in Catalysis "UniSysCat"DFG, 392923329, GRK 2473: Bioaktive Peptide - Innovative Aspekte zur Synthese und BiosyntheseDFG, 426290502, Erfassung der strukturellen Organisation des Mycoplasma pneumoniae Proteoms mittels in-Zell Crosslinking-Massenspektrometri

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Not AvailableThe present investigation was carried out to determine the genetic diversity among ninety five rice germplasm lines along with six checks by using principal component analysis. Principal component analysis was utilized to examine the variation and to estimate the relative contribution of various traits for total variability. There are six axes which accounted for 71.37% cumulative variance of the total variability for twenty agro-morphological and quality traits. PC1 accounted 23.48% of the total variability contributed by the traits like amylose content, days to maturity, days to 50% flowering, total grains per panicle, filled grains per panicle, grain weight per panicle, elongation ratio and chaffy grains per panicle. PC2 accounted 12.45% of the total variation and the traits viz. total grains per panicle, filled grains per panicle, chaffy grains per panicle, kernel breadth and alkali spreading value contribute to the variation. Component 3 had the contribution from the characters like chaffy grains per panicle, grain yield per plant, kernel length, length/breadth ratio, total grains per panicle, alkali spreading value, water uptake and filled grains per panicle which accounted for 10.62% of the total variation. Grain quality characters like kernel length after cooking and elongation ratio had contributed 9.97% of the total variation in PC4. PC5 and 6 accounted 8.03% and 6.82% of the total variability respectively and contributed by the traits like spikelet fertility, filled grains per panicle, ear bearing tillers per plant, total grains per panicle and alkali spreading value. Thus, the results revealed vast genetic variability exists in the studied germplasm lines and can be used for various breeding programmes for improvement in yield and quality.Not Availabl