Diderm bacteria,characterized by an additional lipid membrane layer known as the outer membrane,fold their outer membrane proteins(OMPs)via theβ-barrel assembly machinery(BAM)complex.Understanding how the BAM complex...Diderm bacteria,characterized by an additional lipid membrane layer known as the outer membrane,fold their outer membrane proteins(OMPs)via theβ-barrel assembly machinery(BAM)complex.Understanding how the BAM complex,particularly its key component BamA,assists in OMP folding remains crucial in bacterial cell biology.Recent research has focused primarily on the structural and functional characteristics of BamA within the Gracilicutes clade,such as in Escherichia coli(E.coli).However,another major evolutionary branch,Terrabacteria,has received comparatively less attention.An example of a Terrabacteria is Deinococcus radiodurans(D.radiodurans),a Gram-positive bacterium that possesses a distinctive outer membrane structure.In this study,we first demonstrated that theβ-barrel domains of BamA are not interchangeable between D.radiodurans and E.coli.The structure of D.radiodurans BamA was subsequently determined at 3.8Åresolution using cryo-electron microscopy,revealing obviously distinct arrangements of extracellular loop 4(ECL4)and ECL6 after structural comparison with their counterparts in gracilicutes.Despite the overall similarity in the topology of theβ-barrel domain,our results indicate that certain ECLs have evolved into distinct structures between the Terrabacteria and Gracilicutes clades.While BamA and its function are generally conserved across diderm bacterial species,our findings underscore the evolutionary diversity of this core OMP folder among bacteria,offering new insights into bacterial physiology and evolutionary biology.展开更多
Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time...Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time.Recently,the FtsZ-ring was found to exhibit dynamic treadmilling along the circumference of the division site,driven by GTP hydrolysis.This apparently directional motion of FtsZ seems to drive the movement of septal cell wall synthesis enzymes and to play an important role in modulating cell envelope constriction and septum morphogenesis.However,the relationship between FtsZ’s treadmilling dynamics and cell wall synthesis varies in different bacteria.More importantly,the biophysical and molecular mechanisms governing these dynamic processes are unclear.In this viewpoint,we will focus on some new and exciting studies surrounding this topic and discuss potential mechanisms that underlie how FtsZ’s treadmilling dynamics might regulate septal cell wall synthesis and cell division.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(WK9100000063)the Fundamental Research Funds for the Central Universities(WK9100000031)+3 种基金the National Natural Science Foundation of China(32270035,32271241)the Anhui Provincial Natural Science Foundation(2208085MC40,2008085QC98)the Talent Fund Project of Biomedical Sciences and Health Laboratory of Anhui Province,University of Science and Technology of China(BJ9100000003)the start-up funding from the University of Science and Technology of China(KY9100000034,KJ2070000082).
文摘Diderm bacteria,characterized by an additional lipid membrane layer known as the outer membrane,fold their outer membrane proteins(OMPs)via theβ-barrel assembly machinery(BAM)complex.Understanding how the BAM complex,particularly its key component BamA,assists in OMP folding remains crucial in bacterial cell biology.Recent research has focused primarily on the structural and functional characteristics of BamA within the Gracilicutes clade,such as in Escherichia coli(E.coli).However,another major evolutionary branch,Terrabacteria,has received comparatively less attention.An example of a Terrabacteria is Deinococcus radiodurans(D.radiodurans),a Gram-positive bacterium that possesses a distinctive outer membrane structure.In this study,we first demonstrated that theβ-barrel domains of BamA are not interchangeable between D.radiodurans and E.coli.The structure of D.radiodurans BamA was subsequently determined at 3.8Åresolution using cryo-electron microscopy,revealing obviously distinct arrangements of extracellular loop 4(ECL4)and ECL6 after structural comparison with their counterparts in gracilicutes.Despite the overall similarity in the topology of theβ-barrel domain,our results indicate that certain ECLs have evolved into distinct structures between the Terrabacteria and Gracilicutes clades.While BamA and its function are generally conserved across diderm bacterial species,our findings underscore the evolutionary diversity of this core OMP folder among bacteria,offering new insights into bacterial physiology and evolutionary biology.
基金This work is supported by the start-up funding by the University of Science and Technology of China KJ2070000083(X.Y)and KY9100000035(X.Y).
文摘Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time.Recently,the FtsZ-ring was found to exhibit dynamic treadmilling along the circumference of the division site,driven by GTP hydrolysis.This apparently directional motion of FtsZ seems to drive the movement of septal cell wall synthesis enzymes and to play an important role in modulating cell envelope constriction and septum morphogenesis.However,the relationship between FtsZ’s treadmilling dynamics and cell wall synthesis varies in different bacteria.More importantly,the biophysical and molecular mechanisms governing these dynamic processes are unclear.In this viewpoint,we will focus on some new and exciting studies surrounding this topic and discuss potential mechanisms that underlie how FtsZ’s treadmilling dynamics might regulate septal cell wall synthesis and cell division.
