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A common core for binding single‐stranded DNA: structural comparison of the single‐stranded DNA‐binding proteins (SSB) from E. coli and human mitochondria
Author(s) -
Webster Gordon,
Genschel Jochen,
Curth Ute,
Urbanke Claus,
Kang ChulHee,
Hilgenfeld Rolf
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00747-3
Subject(s) - heterotetramer , dimer , dna , single stranded binding protein , chemistry , biology , protein structure , binding site , dna binding protein , biochemistry , biophysics , protein subunit , transcription factor , gene , organic chemistry
The crystal structure of the DNA‐binding domain of E. coli SSB ( Eco SSB) has been determined to a resolution of 2.5 Å. This is the first reported structure of a prokaryotic SSB. The structure of the DNA‐binding domain of the E. coli protein is compared to that of the human mitochondrial SSB ( Hs mtSSB). In spite of the relatively low sequence identity between them, the two proteins display a high degree of structural similarity. Eco SSB crystallises with two dimers in the asymmetric unit, unlike Hs mtSSB which contains only a dimer. This is probably a consequence of the different polypeptide chain lengths in the Eco SSB heterotetramer. Crucial differences in the dimer‐dimer interface of Eco SSB may account for the inability of Eco SSB and Hs mtSSB to form cross‐species heterotetramers, in contrast to many bacterial SSBs.