Structural basis of antifreeze activity of a bacterial multi-domain antifreeze protein
Structural basis of antifreeze activity of a bacterial multi-domain antifreeze protein
复制标题
细菌多结构域抗冻蛋白抗冻活性的结构基础
作者：
Chen Wang;S. Pakhomova;M. Newcomer;B. Christner;B. Luo
抗冻蛋白（AFPs）通过影响冰的形成和/或结构来提高生活在寒冷环境中的生物的存活率。我们报道了第一个被表征的多域AFP的晶体结构。这两个冰结合域在结构上是相似的。每一个都由一个三角形截面的不规则β-螺旋和一个平行于β-螺旋一侧的长α-螺旋组成。两个结构域都通过疏水相互作用稳定下来。在每个结构域的β-螺旋的同一面上的一个平面被确定为冰结合位点。将冰结合位点上任何较小的残基突变为较大的残基，都会降低抗冻活性。结构域A中Leu174的庞大侧链在空间上阻碍了水分子与蛋白质骨架的结合，这部分解释了为什么结构域A的抗冻活性不如结构域b。我们的数据为理解该蛋白两个结构域之间的抗冻活性差异以及冰结合位点的结构差异如何影响afp活性提供了分子基础。
Antifreeze proteins (AFPs) enhance the survival of organisms inhabiting cold environments by affecting the formation and/or structure of ice. We report the crystal structure of the first multi-domain AFP that has been characterized. The two ice binding domains are structurally similar. Each consists of an irregular β-helix with a triangular cross-section and a long α-helix that runs parallel on one side of the β-helix. Both domains are stabilized by hydrophobic interactions. A flat plane on the same face of each domain’s β-helix was identified as the ice binding site. Mutating any of the smaller residues on the ice binding site to bulkier ones decreased the antifreeze activity. The bulky side chain of Leu174 in domain A sterically hinders the binding of water molecules to the protein backbone, partially explaining why antifreeze activity by domain A is inferior to that of domain B. Our data provide a molecular basis for understanding differences in antifreeze activity between the two domains of this protein and general insight on how structural differences in the ice-binding sites affect the activity of AFPs.
影响因子：
2.9
作者：
M. Loewen;H. Chao;M. Houston;J. Baardsnes;R. Hodges;C. Kay;B. Sykes;F. Sönnichsen;P. Davies
通讯作者：
M. Loewen;H. Chao;M. Houston;J. Baardsnes;R. Hodges;C. Kay;B. Sykes;F. Sönnichsen;P. Davies
影响因子：
2.9
作者：
Chao, HM;Houston, ME;Sonnichsen, FD
通讯作者：
Sonnichsen, FD