3e1s
From Proteopedia
Structure of an N-terminal truncation of Deinococcus radiodurans RecD2
Structural highlights
Function[RECDL_DEIRA] DNA-dependent ATPase (ssDNA better than dsDNA) and ATP-dependent 5'-3' DNA helicase. Appears to move along DNA in single base steps, powered by hydrolysis of 1 molecule of ATP. Has low processivity; short (20 bp) substrates with 5'-overhangs or forked ends are the best substrates, is much less efficient on 52 or 76 bp substrates with 5'- overhangs. The presence of single-stranded DNA-binding protein (SSB) increases unwinding 4-5 fold. Has no activity on blunt DNA or DNA with 3'-overhangs. Requires at least 10 bases of 5'-ssDNA for helicase activity.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe molecular mechanism of superfamily 1Balpha helicases remains unclear. We present here the crystal structure of the RecD2 helicase from Deinococcus radiodurans at 2.2-A resolution. The structure reveals the folds of the 1B and 2B domains of RecD that were poorly ordered in the structure of the Escherichia coli RecBCD enzyme complex reported previously. The 2B domain adopts an SH3 fold which, although common in eukaryotes, is extremely rare in bacterial systems. In addition, the D. radiodurans RecD2 structure has aided us in deciphering lower resolution (3.6 A) electron density maps for the E. coli RecBCD enzyme in complex with a long DNA substrate that interacts with the RecD subunit. Taken together, these structures indicated an important role for the 1B domain of RecD, a beta-hairpin that extends from the surface of the 1A domain and interacts with the DNA substrate. On the basis of these structural data, we designed a mutant RecD2 helicase that lacks this pin. The 'pin-less' mutant protein is a fully active ssDNA-dependent ATPase but totally lacks helicase activity. DNA binding to RecD: role of the 1B domain in SF1B helicase activity.,Saikrishnan K, Griffiths SP, Cook N, Court R, Wigley DB EMBO J. 2008 Aug 20;27(16):2222-9. Epub 2008 Jul 31. PMID:18668125[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||
