General Information

Database accession: MF2120011 Original MFIB entry

Name: Cell division factor ZapB

PDB ID: 2jee PDBe

Experimental method: X-ray (2.8 Å)

Assembly: Homodimer

Source organism: Escherichia coli

Primer 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 PubMed

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.


Function and Biology 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 GeneOntology

Biological process:

FtsZ-dependent cytokinesis FtsZ-dependent cytokinesis GeneOntology

cell septum assembly cell septum assembly GeneOntology

Cellular component:

cytosol cytosol GeneOntology

cell division site cell division site GeneOntology

Structure Summary Structural annotations of the participating protein chains.

Entry contents: 2 distinct polypeptide molecules

Chains: A, B

Notes: Chains C and D were removed as chains A and B represent the biologically relevant dimer.

Number of unique protein segments: 1


Chain A

Name: Cell division protein ZapB

Source organism: Escherichia coli (strain K12)

Length: 81 residues

Sequence:Sequence according to the corresponding UniProt protein segmentMTMSLEVFEKLEAKVQQAIDTITLLQMEIEELKEKNNSLSQEVQNAQHQREELERENNHLKEQQNGWQERLQALLGRMEEV

UniProtKB AC: P0AF36 (positions: 1-81) UniProt

UniRef90 AC: UniRef90_A7ZUE3 (positions: 1-81) UniRef90

Chain B

Name: Cell division protein ZapB

Source organism: Escherichia coli (strain K12)

Length: 81 residues

Sequence:Sequence according to the corresponding UniProt protein segmentMTMSLEVFEKLEAKVQQAIDTITLLQMEIEELKEKNNSLSQEVQNAQHQREELERENNHLKEQQNGWQERLQALLGRMEEV

UniProtKB AC: P0AF36 (positions: 1-81) UniProt

UniRef90 AC: UniRef90_A7ZUE3 (positions: 1-81) UniRef90

Evidence Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding.

Evidence level: Direct evidence

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:

None

Chain B:

None

The molecule viewer shows our modified stucture.

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