6fvm
From Proteopedia
Mutant DNA polymerase sliding clamp from Escherichia coli with bound P7 peptide
Structural highlights
Function[DPO3B_ECO57] Confers DNA tethering and processivity to DNA polymerases and other proteins. Acts as a clamp, forming a ring around DNA (a reaction catalyzed by the clamp-loading complex) which diffuses in an ATP-independent manner freely and bidirectionally along dsDNA. Initially characterized for its ability to contact the catalytic subunit of DNA polymerase III (Pol III), a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria; Pol III exhibits 3'-5' exonuclease proofreading activity. The beta chain is required for initiation of replication as well as for processivity of DNA replication.[UniProtKB:P0A988] Publication Abstract from PubMedBacterial sliding clamps control the access of DNA polymerases to the replication fork and are appealing targets for antibacterial drug development. It is therefore essential to decipher the polymerase-clamp binding mode across various bacterial species. Here, two residues of the E. coli clamp binding pocket, (Ec)S346 and (Ec)M362, and their cognate residues in M. tuberculosis and B. subtilis clamps, were mutated. The effects of these mutations on the interaction of a model peptide with these variant clamps were evaluated by thermodynamic, molecular dynamics, X-rays crystallography, and biochemical analyses. (Ec)M362 and corresponding residues in Gram positive clamps occupy a strategic position where a mobile residue is essential for an efficient peptide interaction. (Ec)S346 has a more subtle function that modulates the pocket folding dynamics, while the equivalent residue in B. subtilis is essential for polymerase activity and might therefore be a Gram positive-specific molecular marker. Finally, the peptide binds through an induced-fit process to Gram negative and positive pockets, but the complex stability varies according to a pocket-specific network of interactions. Interaction of a Model Peptide on Gram Negative and Gram Positive Bacterial Sliding Clamps.,Andre C, Martiel I, Wolff P, Landolfo M, Lorber B, Silva da Veiga C, Dejaegere A, Dumas P, Guichard G, Olieric V, Wagner J, Burnouf DY ACS Infect Dis. 2019 Apr 5. doi: 10.1021/acsinfecdis.9b00089. PMID:30912430[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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