Nir2碳端结构域的晶体结构

Nir2蛋白具有多个结构域，在生物体中可能发挥多种生理功能。本实验用MAD软件对大肠杆菌BL21（plys）原核表达的Nir2蛋白碳端进行了晶体结构分析。结果显示，硒蛋氨酸取代蛋白晶体及未取代蛋白晶体同属空间群P212121,晶胞参数a=109.468 Å, b=120.621 Å, c=70.315 Å，分辨率分别为2.2 Å和2.7 Å。一个不对称单位含有三个分子，含水量为48%。Nir2蛋白碳端由C片层和N片层构成，其中C片层与钙ATPase的催化区域P相似，N片层为许多不相关的功能性蛋白所共有。研究证明二者之间的静电作用是影响Nir2蛋白碳端与Pyk2 FERM区域结合的主要因素。该晶体结构的分析结果为进一步研究Nir2蛋白碳端的潜在功能提供了结构基础。

The crystal structure of Nir2 C-terminal domain

Nir2 is a multiple-domain protein and may play several biological roles. The crystal structure is solved by using MAD method of Nir2 C-terminal domain overexpressed in bacteria E.coli BL21(plys). Both unsubstituted and Selenomethionine-substituted crystals belong to space group P2_12_12_1 (a=109.468(A°), b=120.621(A°), c=70.315(A°), α=β=γ= 90°) and diffract to 2.2(A°)and 2.7(A°), respectively. There are three molecules in one asymmetrical unit and solvent content was 48%. The structure reveals that Nir2 C-terminal domain consists of N lobe and C lobe, the C lobe is similar to the catalytic domain P of calcium ATPase, and N lobe can be found in many functionally unrelated proteins.The results suggest that electrostatic interaction between them is the key factor for the binding of Nir2 C-terminal domain to Pyk2 FERM domain.