3vx4

Publication Abstract from PubMed

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.

Boundary of the Nucleotide-Binding Domain of Streptococcus ComA Based on Functional and Structural Analysis.,Ishii S, Yano T, Okamoto A, Murakawa T, Hayashi H Biochemistry. 2013 Apr 16;52(15):2545-55. doi: 10.1021/bi3017069. Epub 2013 Apr, 5. PMID:23534432^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.