TopBP1, also termed DNA topoisomerase II-beta-binding protein 1, functions in DNA replication and damage response. It binds double-stranded DNA breaks and nicks as well as single-stranded DNA [1-4]. It consists of multiple copies of BRCT domains, wit ...
TopBP1, also termed DNA topoisomerase II-beta-binding protein 1, functions in DNA replication and damage response. It binds double-stranded DNA breaks and nicks as well as single-stranded DNA [1-4]. It consists of multiple copies of BRCT domains, with a triple tandem BRCT domains at the N-terminal (designated BRCT0, BRCT1 and BRCT2), also observed in ECT2 that may represent a new type of consecutive BRCT domains [1-3]. This entry represents the first BRCT domain (BRCT0) of TopBP1 [1-4]. BRCT1/2 are included in Pfam:PF00533. Although ECT2 and TopBP1 share a similar cylinder-like crystal structure and distribution of secondary structure, some helices exhibit different orientations especially in the BRCT0 domain.
This is a BRCT domain that appears in duplicate in most member sequences. BRCT domains are peptide- and phosphopeptide-binding modules. BRCT domains are present in a number of proteins involved in DNA checkpoint controls and DNA repair [1,2].
The BRCT domain is found predominantly in proteins involved in cell cycle checkpoint functions responsive to DNA damage. The BRCT domain of XRCC1 forms a homodimer in the crystal structure. This suggests that pairs of BRCT domains associate as homo- ...
The BRCT domain is found predominantly in proteins involved in cell cycle checkpoint functions responsive to DNA damage. The BRCT domain of XRCC1 forms a homodimer in the crystal structure. This suggests that pairs of BRCT domains associate as homo- or heterodimers. BRCT domains are often found as tandem-repeat pairs [2]. Structures of the BRCA1 BRCT domains revealed a basis for a widely utilised head-to-tail BRCT-BRCT oligomerisation mode [3]. This conserved tandem BRCT architecture facilitates formation of the canonical BRCT phospho-peptide interaction cleft at a groove between the BRCT domains. Disease associated missense and nonsense mutations in the BRCA1 BRCT domains disrupt peptide binding by directly occluding this peptide binding groove, or by disrupting key conserved BRCT core folding determinants [5].