Title: A novel fold in the TraI relaxase-helicase c-terminal domain is essential for conjugative DNA transfer. | Journal: Journal of molecular biology. 2009 Feb;386(2):554-68 | Authors: Guogas LM, Kennedy SA, Lee JH, Redinbo MR. | Abstract: TraI relaxase-helicase is the central catalytic component of the multiprotein relaxosome complex responsible for conjugative DNA transfer (CDT) between bacterial cells. CDT is a primary mechanism for the lateral propagation of microbial genetic material, including the spread of antibiotic resistance genes. The 2.4-A resolution crystal structure of the C-terminal domain of the multifunctional Escherichia coli F (fertility) plasmid TraI protein is presented, and specific structural regions essential for CDT are identified. The crystal structure reveals a novel fold composed of a 28-residue N-terminal alpha-domain connected by a proline-rich loop to a compact alpha/beta-domain. Both the globular nature of the alpha/beta-domain and the presence as well as rigidity of the proline-rich loop are required for DNA transfer and single-stranded DNA binding. Taken together, these data establish the specific structural features of this noncatalytic domain that are essential to DNA conjugation. | See full PubMed entry: http://www.ncbi.nlm.nih.gov/pubmed/19136009 |
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