PDBsum entry 3vx4

Transport protein

PDB id: 3vx4

Contents

Protein chains

239 a.a.

Ligands

ATP ×2

Metals

_MG ×2

Waters ×148

PDB id:

3vx4

Name:

Transport protein

Title:

Crystal structure of the nucleotide-binding domain of s. Mutans coma, a bifunctional atp-binding cassette transporter involved in the quorum-sensing pathway

Structure:

Putative abc transporter, atp-binding protein coma. Chain: a, d. Fragment: nucleotide-binding domain, unp residues 495-760. Engineered: yes. Mutation: yes

Source:

Streptococcus mutans. Organism_taxid: 210007. Strain: atcc 700610 / ua159. Gene: smu_286. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.69Å R-factor: 0.194 R-free: 0.248

Authors:

S.Ishii,T.Yano,A.Okamoto,T.Murakawa,H.Hayashi

Key ref:

S.Ishii et al. (2013). Boundary of the nucleotide-binding domain of Streptococcus ComA based on functional and structural analysis. Biochemistry, 52, 2545-2555. PubMed id: 23534432 DOI: 10.1021/bi3017069

Date:

11-Sep-12 Release date: 17-Apr-13

Protein chains

Q8DW05  (Q8DW05_STRMU) -  ABC transporter, ATP-binding protein ComA from Streptococcus mutans serotype c (strain ATCC 700610 / UA159)

Seq: 760 a.a.

Struc: 239 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1021/bi3017069

Biochemistry 52:2545-2555 (2013)

PubMed id: 23534432

Boundary of the nucleotide-binding domain of Streptococcus ComA based on functional and structural analysis.

S.Ishii, T.Yano, A.Okamoto, T.Murakawa, H.Hayashi.

ABSTRACT

The ATP-binding cassette (ABC) transporter ComA is a key molecule essential for the first step of the quorum-sensing system of Streptococcus. The nucleotide binding domains (NBD) of Streptococcus mutans ComA with different N termini, NBD1 (amino acid residues 495-760), NBD2 (517-760), and NBD3 (528-760), were expressed, purified, and characterized. The shortest NBD3 corresponds to the region commonly defined as NBD in the database searches of ABC transporters. A kinetic analysis showed that the extra N-terminal region conferred a significantly higher ATP hydrolytic activity on the NBD at a neutral pH. Gel-filtration, X-ray crystallography, and mutational analyses suggest that at least four to five residues beyond the N-terminal boundary of NBD3 indeed participate in stabilizing the protein scaffold of the domain structure, thereby facilitating the ATP-dependent dimerization of NBD which is a prerequisite to the catalysis. These findings, together with the presence of a highly conserved glycine residue in this region, support the redefinition of the N-terminal boundary of the NBD of these types of ABC exporters.