Laboratory of Macromolecular Crystallography, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India.
Manipal Academy of Higher Education, India.
FEBS Lett. 2021 May;595(9):1328-1349. doi: 10.1002/1873-3468.14055. Epub 2021 Feb 12.
An assembly of multiprotein complexes achieves chromosomal DNA replication at the replication fork. In eukaryotes, proliferating cell nuclear antigen (PCNA) plays a vital role in the assembly of multiprotein complexes at the replication fork and is essential for cell viability. PCNA from several organisms, including Saccharomyces cerevisiae, has been structurally characterised. However, the structural analyses of PCNA from fungal pathogens are limited. Recently, we have reported that PCNA from the opportunistic fungal pathogen Candida albicans complements the essential functions of ScPCNA in S. cerevisiae. Still, it only partially rescues the loss of ScPCNA when the yeast cells are under genotoxic stress. To understand this further, herein, we have determined the crystal structure of CaPCNA and compared that with the existing structures of other fungal and human PCNA. Our comparative structural and in-solution small-angle X-ray scattering (SAXS) analyses reveal that CaPCNA forms a stable homotrimer, both in crystal and in solution. It displays noticeable structural alterations in the oligomerisation interface, P-loop and hydrophobic pocket regions, suggesting its differential function in a heterologous system and avenues for developing specific therapeutics. DATABASES: The PDB and SASBDB accession codes for CaPCNA are 7BUP and SASDHQ9, respectively.
多蛋白复合物组装在复制叉处实现染色体 DNA 复制。在真核生物中，增殖细胞核抗原 (PCNA) 在复制叉处多蛋白复合物的组装中起着至关重要的作用，对细胞活力是必需的。包括酿酒酵母在内的几种生物的 PCNA 已被结构表征。然而，真菌病原体 PCNA 的结构分析有限。最近，我们报道了来自机会性真菌病原体白念珠菌的 PCNA 能够补充酿酒酵母中 ScPCNA 的必需功能。然而，当酵母细胞受到遗传毒性应激时，它只能部分挽救 ScPCNA 的缺失。为了进一步了解这一点，在此，我们确定了 CaPCNA 的晶体结构，并将其与其他真菌和人类 PCNA 的现有结构进行了比较。我们的比较结构和溶液中的小角 X 射线散射 (SAXS) 分析表明，CaPCNA 在晶体和溶液中均形成稳定的同源三聚体。它在寡聚化界面、P 环和疏水性口袋区域显示出明显的结构改变，表明其在异源系统中的功能不同，为开发特定的治疗方法提供了途径。数据库：CaPCNA 的 PDB 和 SASBDB 访问代码分别为 7BUP 和 SASDHQ9。
