Architecture of bacterial replication initiation complexes: orisomes from four unrelated bacteria

• Published in: Biochemical journal 2005-07, Vol.389 (Pt 2), p.471-481
• Main Authors: Zawilak-Pawlik, Anna, Kois, Agnieszka, Majka, Jerzy, Jakimowicz, Dagmara, Smulczyk-Krawczyszyn, Aleksandra, Messer, Walter, Zakrzewska-Czerwińska, Jolanta
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Base Sequence; Cell Division; DNA Replication - genetics; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - metabolism; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Eubacteria; Gene Expression Regulation, Bacterial; Helicobacter pylori; Helicobacter pylori - genetics; Helicobacter pylori - metabolism; Molecular Sequence Data; Mycobacterium tuberculosis; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - metabolism; Origin Recognition Complex - genetics; Origin Recognition Complex - metabolism; Replication Origin - genetics; Sequence Homology, Amino Acid; Species Specificity; Streptomyces coelicolor; Streptomyces coelicolor - genetics; Streptomyces coelicolor - metabolism
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/BJ20050143

Bacterial chromosome replication is mediated by single initiator protein, DnaA, that interacts specifically with multiple DnaA boxes located within the origin (oriC). We compared the architecture of the DnaA-origin complexes of evolutionarily distantly related eubacteria: two Gram-negative organisms, Escherichia coli and Helicobacter pylori, and two Gram-positive organisms, Mycobacterium tuberculosis and Streptomyces coelicolor. Their origins vary in size (from approx. 200 to 1000 bp) and number of DnaA boxes (from 5 to 19). The results indicate that: (i) different DnaA proteins exhibit various affinities toward single DnaA boxes, (ii) spatial arrangement of two DnaA boxes is crucial for the H. pylori and S. coelicolor DnaA proteins, but not for E. coli and M. tuberculosis proteins, and (iii) the oriC regions are optimally adjusted to their cognate DnaA proteins. The primary functions of multiple DnaA boxes are to determine the positioning and order of assembly of the DnaA molecules. Gradual transition from the sequence-specific binding of the DnaA protein to binding through co-operative protein-protein interactions seems to be a common conserved strategy to generate oligomeric initiator complexes bound to multiple sites within the chromosomal, plasmid and virial origins.