Inoguchi Noriko, Oshlo Jake R, Natarajan Chandrasekhar, Weber Roy E, Fago Angela, Storz Jay F, Moriyama Hideaki
School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2013 Apr 1;69(Pt 4):393-8. doi: 10.1107/S1744309113005708. Epub 2013 Mar 28.
The deer mouse, Peromyscus maniculatus, exhibits altitude-associated variation in hemoglobin oxygen affinity. To examine the structural basis of this functional variation, the structure of the hemoglobin was solved. Recombinant hemoglobin was expressed in Escherichia coli and was purified by ion-exchange chromatography. Recombinant hemoglobin was crystallized by the hanging-drop vapor-diffusion method using polyethylene glycol as a precipitant. The obtained orthorhombic crystal contained two subunits in the asymmetric unit. The refined structure was interpreted as the aquo-met form. Structural comparisons were performed among hemoglobins from deer mouse, house mouse and human. In contrast to human hemoglobin, deer mouse hemoglobin lacks the hydrogen bond between α1Trp14 in the A helix and α1Thr67 in the E helix owing to the Thr67Ala substitution. In addition, deer mouse hemoglobin has a unique hydrogen bond at the α1β1 interface between residues α1Cys34 and β1Ser128.
鹿鼠（Peromyscus maniculatus）的血红蛋白氧亲和力呈现出与海拔相关的变化。为了研究这种功能变化的结构基础，解析了血红蛋白的结构。重组血红蛋白在大肠杆菌中表达，并通过离子交换色谱法进行纯化。使用聚乙二醇作为沉淀剂，通过悬滴气相扩散法使重组血红蛋白结晶。得到的正交晶体在不对称单元中包含两个亚基。精制后的结构被解释为水合高铁形式。对鹿鼠、家鼠和人类的血红蛋白进行了结构比较。与人类血红蛋白不同，由于苏氨酸67被丙氨酸取代，鹿鼠血红蛋白在A螺旋中的α1Trp14和E螺旋中的α1Thr67之间缺乏氢键。此外，鹿鼠血红蛋白在α1Cys34和β1Ser128残基之间的α1β1界面处有一个独特的氢键。
