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
The tubulin-like protein FtsZ assembles into the Z ring that leads to the assembly and activation of the division machinery in most bacteria.ZapA,a widely conserved protein that interacts with FtsZ,plays a pivotal rol...The tubulin-like protein FtsZ assembles into the Z ring that leads to the assembly and activation of the division machinery in most bacteria.ZapA,a widely conserved protein that interacts with FtsZ,plays a pivotal role in organizing FtsZ filaments into a coherent Z ring.Previous studies revealed that ZapA forms a dumbbell-like tetramer that binds cooperatively to FtsZ filaments and aligns them in parallel,leading to the straightening and organization of FtsZ filament bundles.However,how ZapA interacts with FtsZ remains obscure.Here,we reveal that ZapA uses a two-pronged mechanism to interact with FtsZ to facilitate Z ring formation in Escherichia coli.We find that mutations affecting surface-exposed residues at the junction between adjacent FtsZ subunits in a filament as well as in an N-terminal motif of FtsZ weaken its interaction with ZapA in vivo and in vitro,indicating that ZapA binds to these regions of FtsZ.Consistent with this,ZapA prefers FtsZ polymers over monomeric FtsZ molecules and site-specific crosslinking confirmed that the dimer head domain of ZapA is in contact with the junction of FtsZ subunits.As a result,disruption of the putative interaction interfaces between FtsZ and ZapA abolishes the midcell localization of ZapA.Taken together,our results suggest that ZapA tetramers grab the N-terminal tails of FtsZ and bind to the junctions between FtsZ subunits in the filament to straighten and crosslink FtsZ filaments into the Z ring.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.
基金supported by the National Natural Science Foundation of China(grant Nos.32070032 and 32270049)the Fundamental Research Funds for the Central Universities(grant No.2042021kf0198)+3 种基金the Young Top-notch Talent Cultivation Program of China to S.D.S.H.'s research is supported by the National Natural Science Foundation of China(grant Nos.32161133002 and 62072199)D.Y.,X.W.,H.H.,and X.Y.'s research is supported by the National Natural Science Foundation of China(grant No.32270035)the Anhui Provincial Natural Science Foundation(Award No.2208085MC40).
文摘The tubulin-like protein FtsZ assembles into the Z ring that leads to the assembly and activation of the division machinery in most bacteria.ZapA,a widely conserved protein that interacts with FtsZ,plays a pivotal role in organizing FtsZ filaments into a coherent Z ring.Previous studies revealed that ZapA forms a dumbbell-like tetramer that binds cooperatively to FtsZ filaments and aligns them in parallel,leading to the straightening and organization of FtsZ filament bundles.However,how ZapA interacts with FtsZ remains obscure.Here,we reveal that ZapA uses a two-pronged mechanism to interact with FtsZ to facilitate Z ring formation in Escherichia coli.We find that mutations affecting surface-exposed residues at the junction between adjacent FtsZ subunits in a filament as well as in an N-terminal motif of FtsZ weaken its interaction with ZapA in vivo and in vitro,indicating that ZapA binds to these regions of FtsZ.Consistent with this,ZapA prefers FtsZ polymers over monomeric FtsZ molecules and site-specific crosslinking confirmed that the dimer head domain of ZapA is in contact with the junction of FtsZ subunits.As a result,disruption of the putative interaction interfaces between FtsZ and ZapA abolishes the midcell localization of ZapA.Taken together,our results suggest that ZapA tetramers grab the N-terminal tails of FtsZ and bind to the junctions between FtsZ subunits in the filament to straighten and crosslink FtsZ filaments into the Z ring.
