Biology subjects

Masrati, G.

Publications and source records attributed to Masrati, G..

2 recordsLinked to original sources

bioRxiv2021

Structure of plant PSI-plastocyanin complex reveals strong hydrophobic interactions.

Photosystem I is defined as plastocyanin-ferredoxin oxidoreductase. Taking advantage of genetic engineering, kinetic analyses and cryo-EM, our data provide novel mechanistic insights into binding and electron transfer between PSI and Pc. Structural data at 2.74 [A] resolution reveals strong hydrophobic interactions in the plant PSI-Pc ternary complex, leading to exclusion of water molecules from PsaA-PsaB / Pc interface once the PSI-Pc complex forms. Upon oxidation of Pc, a slight tilt of bound oxidized Pc allows water molecules to accommodate the space between Pc and PSI to drive Pc dissociation. Such a scenario is consistent with the six times larger dissociation constant of oxidized as compared to reduced Pc and mechanistically explains how this molecular machine optimized electron transfer for fast turnover. One Sentence SummaryGenetic engineering, kinetics and cryo-EM structural data reveal a mechanism in a major step of oxygenic photosynthesis

biochemistry↗

bioRxiv2020

The Botrytis cinerea Crh transglycosylae is a cytoplasmic effector triggering plant cell death and defense response

Crh proteins catalyze crosslinking of chitin and glucan polymers in the fugal cell wall. We revealed a novel and unexpected role of Botrytis cinerea BcCrh1 as a cytoplasmic effector and elicitor of plant defense. During saprophytic growth the BcCrh1 protein is localized in vacuoles and ER. Upon plant infection the protein accumulates to high levels in infection cushions, it is then secreted to the apoplast and translocated into plant cells, where it induces cell death and defense responses. Two regions of 53 and 35 amino acids were found sufficient for protein uptake and cell death induction, respectively. Dimerization of BcCrh proteins was necessary for the transglycosylation activity and proper fungal development, while the monomeric proteins was sufficient for induction of cell death. Arabidopsis lines expressing the bccrh1 gene had reduced sensitivity to B. cinerea, demonstrating the potential use of the protein in plant immunization against necrotrophic pathogens.

microbiology↗