Database accession: MF2120011
Name: Cell division factor ZapB
PDB ID: 2jee
Experimental method: X-ray (2.80 Å)
Assembly: Homodimer
Source organism: Escherichia coli
Primary publication of the structure:
Ebersbach G, Galli E, Møller-Jensen J, Löwe J, Gerdes K
Novel coiled-coil cell division factor ZapB stimulates Z ring assembly and cell division.
(2008) Mol. Microbiol. 68: 720-35
PMID: 18394147
Abstract:
Formation of the Z ring is the first known event in bacterial cell division. However, it is not yet known how the assembly and contraction of the Z ring are regulated. Here, we identify a novel cell division factor ZapB in Escherichia coli that simultaneously stimulates Z ring assembly and cell division. Deletion of zapB resulted in delayed cell division and the formation of ectopic Z rings and spirals, whereas overexpression of ZapB resulted in nucleoid condensation and aberrant cell divisions. Localization of ZapB to the divisome depended on FtsZ but not FtsA, ZipA or FtsI, and ZapB interacted with FtsZ in a bacterial two-hybrid analysis. The simultaneous inactivation of FtsA and ZipA prevented Z ring assembly and ZapB localization. Time lapse microscopy showed that ZapB-GFP is present at mid-cell in a pattern very similar to that of FtsZ. Cells carrying a zapB deletion and the ftsZ84(ts) allele exhibited a synthetic sick phenotype and aberrant cell divisions. The crystal structure showed that ZapB exists as a dimer that is 100% coiled-coil. In vitro, ZapB self-assembled into long filaments and bundles. These results raise the possibility that ZapB stimulates Z ring formation directly via its capacity to self-assemble into larger structures.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
identical protein binding identical protein binding
Biological process:
division septum assembly division septum assembly
FtsZ-dependent cytokinesis FtsZ-dependent cytokinesis
Cellular component:
cell division site cell division site
cytosol cytosol
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, B
Notes: All chains according to the most probable oligomerization state stored in PDBe were considered.
Number of unique protein segments: 1
Name: Cell division protein ZapB
Source organism: Escherichia coli
Length: 81 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMTMSLEVFEKLEAKVQQAIDTITLLQMEIEELKEKNNSLSQEVQNAQHQREELERENNHLKEQQNGWQERLQALLGRMEEV
UniProtKB AC: P0AF36 (positions: 3-81)
Coverage: 97%
Name: Cell division protein ZapB
Source organism: Escherichia coli
Length: 81 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMTMSLEVFEKLEAKVQQAIDTITLLQMEIEELKEKNNSLSQEVQNAQHQREELERENNHLKEQQNGWQERLQALLGRMEEV
UniProtKB AC: P0AF36 (positions: 3-81)
Coverage: 97%
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Representative domain in related structures: -
Evidence level: Direct evidence
Evidence coverage: The full structure participates in mutual synergistic folding.
Complex Evidence:
The subunits in the structure are bound via coiled coil interactions (PMID:18394147). Coiled coils are highly versatile folding units (PMID:11166216), where the formation of the structure and the interaction between subunits is almost ubiquitously linked. This cooperative nature of binding and folding that results in a two-step process has been demonstrated for coiled coils with varying oligomeric state from dimers (PMID:9811815) and trimers (PMID:10933510) up to heptamers (PMID:17030805). While the interaction and folding are linked, in certain cases there can be significant residual structure before association (PMID:8401212). However, these residual structural elements usually encompass 1-2 turns of helices that serve as a 'nucleation site' driving interaction and helix formation (zipping up) (PMID:17438295), thus even in these cases monomeric coiled coil subunits cannot be considered to have a stable structure.
Chain A:
N/A
Chain B:
N/A
Surface and contacts features:
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). No related structure was found in the MFIB database.
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