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The structural details of the interaction of single‐stranded DNA binding protein hSSB2 (NABP1/OBFC2A) with UV‐damaged DNA
Author(s) -
Lawson Teegan,
ElKamand Serene,
Boucher Didier,
Duong Duc Cong,
Kariawasam Ruvini,
Bonvin Alexandre M. J. J.,
Richard Derek J.,
Gamsjaeger Roland,
Cubeddu Liza
Publication year - 2020
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.25806
Subject(s) - dna , hmg box , oligonucleotide , dna damage , dna binding protein , dna binding domain , biochemistry , dna repair , chemistry , dna replication , pyrimidine dimer , binding domain , biology , biophysics , plasma protein binding , binding site , gene , transcription factor
Single‐stranded DNA‐binding proteins (SSBs) are required for all known DNA metabolic events such as DNA replication, recombination and repair. While a wealth of structural and functional data is available on the essential human SSB, hSSB1 (NABP2/OBFC2B), the close homolog hSSB2 (NABP1/OBFC2A) remains relatively uncharacterized. Both SSBs possess a well‐structured OB (oligonucleotide/oligosaccharide‐binding) domain that is able to recognize single‐stranded DNA (ssDNA) followed by a flexible carboxyl‐tail implicated in the interaction with other proteins. Despite the high sequence similarity of the OB domain, several recent studies have revealed distinct functional differences between hSSB1 and hSSB2. In this study, we show that hSSB2 is able to recognize cyclobutane pyrimidine dimers (CPD) that form in cellular DNA as a consequence of UV damage. Using a combination of biolayer interferometry and NMR, we determine the molecular details of the binding of the OB domain of hSSB2 to CPD‐containing ssDNA, confirming the role of four key aromatic residues in hSSB2 (W59, Y78, W82, and Y89) that are also conserved in hSSB1. Our structural data thus demonstrate that ssDNA recognition by the OB fold of hSSB2 is highly similar to hSSB1, indicating that one SSB may be able to replace the other in any initial ssDNA binding event. However, any subsequent recruitment of other repair proteins most likely depends on the divergent carboxyl‐tail and as such is likely to be different between hSSB1 and hSSB2.