Crystallization and preliminary X‐ray diffraction data of the complex between human centrin 2 and a peptide from the protein XPC

Centrins are highly conserved calcium‐binding proteins involved in the nucleotide‐excision repair pathway as a subunit of the heterotrimer including the XPC and hHR23B proteins. A complex formed by a Ca 2+ ‐bound human centrin 2 construct (the wild type lacking the first 25 amino acids) with a 17‐mer peptide derived from the XPC sequence (residues Asn847–Arg863) was crystallized. Data were collected to 1.65 Å resolution from crystals grown in 30% monomethyl polyethylene glycol (MPEG) 500, 100 m M NaCl and 100 m M Bicine pH 9.0. Crystals are monoclinic and belong to space group C 2, with two molecules in the asymmetric unit. The unit‐cell parameters are a = 60.28, b  = 59.42, c = 105.14 Å, α = γ = 90, β = 94.67°. A heavy‐atom derivative was obtained by co‐crystallization with Sr 2+ . The substitution was rationalized by calorimetry experiments, which indicate a binding constant for Sr 2+ of 4.0 × 10 4   M −1 .