Crystallization and X-ray diffraction studies of crustacean proliferating cell nuclear antigen

Abstract

Proliferating cell nuclear antigen (PCNA), a member of the sliding clamp family of proteins, interacts specifically with DNA replication and repair proteins through a small peptide motif called the PCNA-interacting protein or PIP box. PCNA is recognized as one of the key proteins involved in DNA metabolism. In the present study, the recombinant PCNA fromLitopenaeus vannamei(LvPCNA) was heterologously overexpressed and purified using metal ion-affinity chromatography. Crystals suitable for diffraction grew overnight using the hanging-drop vapour-diffusion method.LvPCNA crystals belong to space groupC2 with unit-cell parametersa= 144.6,b= 83.4,c= 74.3 Å, β = 117.6°. One data set was processed to 3 Å resolution, with an overallRmeasof 0.09 and a completeness of 93.3%. Initial phases were obtained by molecular replacement using a homology model ofLvPCNA as the search model. Refinement and structural analysis are underway. This report is the first successful crystallographic analysis of a marine crustacean decapod shrimp (L. vannamei) proliferating cell nuclear antigen.