Nucleotide-Induced Conformational Changes in Escherichia coli DnaA Protein Are Required for Bacterial ORC to Pre-RC Conversion at the Chromosomal Origin

International Journal of Molecular Sciences

Rahul Saxena²  Sona Vasudevan²  Digvijay Patil²  Norah Ashoura¹  Julia E. Grimwade¹  Elliott Crooke² 

[1]Department of Biological Sciences, Florida Institute of Technology, 150 West University Blvd, Melbourne, FL 32901, USA

[2]Department of Biochemistry and Molecular & Cellular Biology Georgetown University Medical Center, Washington, DC 20007, USA

关键词: DnaA protein;    AAA+ domain;    molecular docking;    proteolysis;    chromosomal origin;    DNA replication;   

DOI  :  10.3390/ijms161126064

来源: mdpi

【 摘 要 】

DnaA oligomerizes when bound to origins of chromosomal replication. Structural analysis of a truncated form of DnaA from Aquifex aeolicus has provided insight into crucial conformational differences within the AAA+ domain that are specific to the ATP- versus ADP- bound form of DnaA. In this study molecular docking of ATP and ADP onto Escherichia coli DnaA, modeled on the crystal structure of Aquifex aeolicus DnaA, reveals changes in the orientation of amino acid residues within or near the vicinity of the nucleotide-binding pocket. Upon limited proteolysis with trypsin or chymotrypsin ADP-DnaA, but not ATP-DnaA generated relatively stable proteolytic fragments of various sizes. Examined sites of limited protease susceptibility that differ between ATP-DnaA and ADP-DnaA largely reside in the amino terminal half of DnaA. The concentration of adenine nucleotide needed to induce conformational changes, as detected by these protease susceptibilities of DnaA, coincides with the conversion of an inactive bacterial origin recognition complex (bORC) to a replication efficient pre-replication complex (pre-RC) at the E. coli chromosomal origin of replication (oriC).

【 授权许可】

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© 2015 by the authors; licensee MDPI, Basel, Switzerland.