Ultsch M, Braisted A, Maun H R, Eigenbrot C
Department of Structural Biology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080,USA.
Department of Protein Engineering, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
Protein Eng Des Sel. 2017 Sep 1;30(9):619-625. doi: 10.1093/protein/gzx029.
The well-studied B-domain from Staphylococcal protein A is a 59 amino acid three-helix bundle that binds the Fc portion of IgG with a dissociation constant of ~35 nM. The B-domain variant bearing a Gly to Ala mutation (=Z-domain) has been the subject of efforts to minimize a domain's size while retaining its function. We report X-ray crystallographic characterization of three steps in such a process using complexes with Fc: the full three-helix Z-domain, a 34 amino acid two-helix version called Z34C and a 13 amino acid single helix stabilized with an exo-helix tether, called LH1.
对葡萄球菌蛋白A中研究充分的B结构域是一个由59个氨基酸组成的三螺旋束，它以约35 nM的解离常数结合IgG的Fc部分。带有甘氨酸到丙氨酸突变的B结构域变体（=Z结构域）一直是在保留结构域功能的同时尽量减小其大小的研究对象。我们报告了在这样一个过程中使用与Fc的复合物的三个步骤的X射线晶体学表征：完整的三螺旋Z结构域、一个名为Z34C的由34个氨基酸组成的双螺旋版本以及一个由外部螺旋系链稳定的由13个氨基酸组成的单螺旋，称为LH1。
