McDonald J F, Shah A M, Schwalbe R A, Kisiel W, Dahlbäck B, Nelsestuen G L
Department of Biochemistry, University of Minnesota, St. Paul 55108, USA.
Biochemistry. 1997 Apr 29;36(17):5120-7. doi: 10.1021/bi9626160.
Membrane-binding properties of human and bovine forms of vitamin K-dependent proteins Z, S, and C were characterized. Each of these proteins showed unique properties and interspecies differences that correlated with specific amino acid sequence variations in the amino-terminal 45 residues. Protein Z showed 100-fold slower membrane binding and dissociation kinetics relative to other vitamin K-dependent proteins that have been tested. This property seemed to correlate with an extra gamma-carboxyglutamic acid (Gla) residue at position 11 of protein Z. The interspecies difference for protein Z consisted of a higher packing density for the bovine protein on the membrane and a 9-fold slower dissociation rate. Higher affinity correlated with Asp at position 34 of bovine protein Z, where the human protein contains Asn. While both protein S species showed high affinity for the membrane, it was significantly greater for the human protein versus bovine protein S. Again, higher affinity correlated with an Asp (vs Asn) at position 34. Protein C was characterized by binding affinities that were 100-1000-fold lower than the other proteins. Low affinity appeared to be related to loss of Gla-32 (homologous to Gla-33 of protein Z). Interspecies differences of protein C appeared to be related to proline at position 10 (homologous to position 11 of protein Z) of bovine protein C, which produced at least 10-fold lower affinity than the human protein. Comparable substitutions at positions homologous to 11, 33, and 34 of protein Z may also underlie membrane binding behaviors of other vitamin K-dependent proteins. The three-dimensional structure of strontium-prothrombin fragment 1 [Seshadri et al. (1994) Biochemistry 33, 1087] shows that these positions are clustered on the protein surface near strontium-8, another possible candidate for membrane contact. A membrane contact mechanism consisting of an isolated protein-lipid ion pair is proposed. Comparison of naturally occurring vitamin K-dependent proteins has provided possible bases for divergent membrane binding and suggested future approaches to determine biological function.
对人源和牛源维生素K依赖性蛋白Z、S和C的膜结合特性进行了表征。这些蛋白质中的每一种都表现出独特的特性和种间差异，这些差异与氨基末端45个残基中的特定氨基酸序列变异相关。与其他已测试的维生素K依赖性蛋白相比，蛋白Z的膜结合和解离动力学慢100倍。这一特性似乎与蛋白Z第11位的一个额外的γ-羧基谷氨酸（Gla）残基有关。蛋白Z的种间差异包括牛蛋白在膜上的堆积密度更高，解离速率慢9倍。更高的亲和力与牛蛋白Z第34位的天冬氨酸（Asp）相关，而人蛋白在该位置含有天冬酰胺（Asn）。虽然两种蛋白S对膜都表现出高亲和力，但人蛋白S对膜的亲和力明显高于牛蛋白S。同样，更高的亲和力与第34位的天冬氨酸（相对于天冬酰胺）相关。蛋白C的特征是其结合亲和力比其他蛋白质低100 - 1000倍。低亲和力似乎与Gla-32的缺失有关（与蛋白Z的Gla-33同源）。蛋白C的种间差异似乎与牛蛋白C第10位的脯氨酸有关（与蛋白Z的第11位同源），该脯氨酸产生的亲和力比人蛋白至少低10倍。与蛋白Z的第11、33和34位同源位置的类似取代也可能是其他维生素K依赖性蛋白膜结合行为的基础。锶 - 凝血酶原片段1的三维结构[塞沙德里等人（1994年）《生物化学》33卷，第1087页]表明，这些位置聚集在蛋白表面靠近锶 - 8的地方，锶 - 8是膜接触的另一个可能候选者。提出了一种由孤立的蛋白 - 脂质离子对组成的膜接触机制。对天然存在的维生素K依赖性蛋白的比较为不同的膜结合提供了可能的基础，并为确定生物学功能提出了未来的方法。
