Three-dimensional structure of the kringle sequence: structure of prothrombin fragment 1.
Three-dimensional structure of the kringle sequence: structure of prothrombin fragment 1.
复制标题
kringle序列的三维结构：凝血酶原片段1的结构。
DOI：
10.1021/bi00362a001
复制
发表时间：
1986
期刊：
影响因子：
2.9
通讯作者：
Tulinsky,A
中科院分区：
文献类型：
--
作者：
Park,CH;Tulinsky,A
密歇根州立大学密歇根大学化学系，密歇根东兰辛，48824；修订稿收到1986年4月28日摘要：牛凝血酶原片段1的三维结构已在2.8？分辨率下解析。电子密度图清楚地显示了4个二硫键和80%以上的侧链，它们与kringle序列、其前30个残基和十二肽羧基末端完全对应，多糖和片段1氨基末端的前35个残基是无序的，约占结构的40%。Kringle序列的折叠是基于Cys-87-Cys-127和Cys-115-Cys-139(桥的中点之间的4.1°)之间紧密的二硫键van der Waals接触，两条高度保守的(113-118,124-129)/3-结构的反平行链，以及一些保守的芳香族残基的堆积，所有这些都在折叠结构的中心附近。此外，整个折叠似乎被复制为一对堆叠的双链回路，带有一个反平行的开环。Kringle结构的整体形状近似于一个尺寸为11x28x30？的偏心扁平椭球。紧接kringle之前的残基以-螺旋结构为主(Phe-41-Cys-48；Leu-56-Glu-63)。在因子IX、因子X、蛋白C和蛋白Z中保守的残基Phe-41-Trp-42和Tyr-45形成另一个芳香堆叠簇，而Cys-48-Cys-61二硫键环对应于众所周知的/？结构单元。十二肽的羧基末端环间链在其平面上沿环的外围延伸，并与环合的Ser-140-Val-143四肽形成一个/3-结构。凝血中纤维蛋白凝块的产生源于一系列活化反应，在这些反应中，前体糖原分子被转化为酶(Davie&Fujikawa，1975)。此外，在膜和辅酶、钙离子和磷脂表面存在的情况下，这一过程的效率大大提高(Mann，1984)。因此，凝血反应是通过血管损伤部位的级联成分之间的络合作用来定位的。随着时间的推移，细胞纤溶酶原激活剂将纤溶酶原转化为纤溶酶，最终溶解血栓中的纤维蛋白(Jackson&Nmerson，1980)。凝血级联的倒数第二步是维生素K依赖的酶原凝血酶原或凝血因子II(Mr 74000)蛋白水解性转化为凝血酶或凝血因子Ha(Mr 37400)。发生的两个蛋白水解酶是由另一种维生素K依赖的酶，因子Xa(MT 45 300)催化的(Mann，1976)。这种特殊激活的一个关键要求是因子Xa与f的相互作用。这项工作得到了NIH Grant HL25942的支持。
Chang H. Park and Alexander Tulinsky* Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 Received March 18, 1986; Revised Manuscript Received April 28, 1986 abstract: The three-dimensional structure of bovine prothrombin fragment 1 has been solved at 2.8-Á resolution. The electron density clearly reveals four disulfide bridges along with more than 80% of the side chains completely in density, which correspond faithfully to the kringle sequence, its preceding 30 residues, and the dodecapeptide carboxy terminal; the polysaccharideand the first 35 residues of the amino terminal of fragment 1 are disordered or about 40% of the structure. The folding of the kringle sequence is based upon close disulfide van der Waals contacts between Cys-87-Cys-127 and Cys-115-Cys-139 (4.1 Á between midpoints of the bridges), two antiparallel strands of highly conserved (113-118, 124-129)/3-structure, and the stacking of some conserved aromatic residues, all near the center of the folded structure. Moreover, the overall folding appears to be duplicated as a pair of stacked duplex loops with an antiparallel open loop. The overall shape of the kringle structure approximates an eccentric oblate ellipsoid of dimensions 11 x 28 X 30 Á. The residues immediately preceding the kringle are dominated by-helical structure (Phe-41-Cys-48; Leu-56-Glu-63). Residues Phe-41-Trp-42 and Tyr-45, which are conserved in factor IX, factor X, protein C, and protein Z, form another aromatic stacked cluster while the Cys-48-Cys-61 disulfide loop corresponds to the well-known/ß structural unit. The dodecapeptide carboxy-terminalinterkringle chain extends along the periphery of the kringle in its plane and forms a/3-structure with the kringle-closing Ser-140-Val-143 tetrapeptide. e production of the fibrin clot in blood coagulation arises from a cascade of activationreactions in which precursor glycoproenzyme molecules are converted to enzymes (Davie & Fujikawa, 1975). Moreover, the process is accomplished at greatly enhanced efficiency in the presence of membrane and cofactor enzymes, Ca2+ ions, and phospholipid surface (Mann, 1984). Blood coagulation reactions are thusly localized via complexation among cascade components at the site of the vascular injury. With time, cellular plasminogen activators convert plasminogen to plasmin, whichultimately dissolves the fibrin of the blood clot (Jackson & Nemerson, 1980). The penultimate step of the blood coagulation cascade is the proteolytic conversion of the vitamin K dependent zymogen prothrombin or factor II (Mr 74000) to thrombin or factor Ha (Mr 37 400). The two proteolytic cleavages that occur are catalyzed by another vitamin K dependent enzyme, factor Xa (MT 45 300)(Mann, 1976). A crucial requirement of this particular activation is the interaction of factor Xa with f This work was supported by NIH Grant HL25942.