Gettins Peter G W
Department of Biochemistry and Molecular Biology, College of Medicine, University of Illinois at Chicago, 60612-4316, Chicago, IL, USA.
FEBS Lett. 2002 Jul 17;523(1-3):2-6. doi: 10.1016/s0014-5793(02)02924-1.
Proteinase inhibition by serpins requires a 70 A translocation of the proteinase, circumvention of the blocking helix F, and a crushing of the proteinase to render it catalytically incompetent. I propose that temporary displacement of the F-helix during proteinase transit, and its subsequent return after complete passage of the proteinase, not only allows the proteinase to reach its final location, but provides an absolutely essential coupling mechanism for making the final proteinase crushing step energetically favorable. The F-helix is therefore not a passive impediment to proteinase translocation, but a critical, active element in permitting the serpin inhibition mechanism to operate successfully.
丝氨酸蛋白酶抑制剂（serpins）对蛋白酶的抑制作用需要蛋白酶发生70埃的移位，绕过阻断螺旋F，并使蛋白酶受到挤压从而使其失去催化活性。我提出，在蛋白酶通过期间F螺旋的暂时移位，以及在蛋白酶完全通过后其随后的复位，不仅能使蛋白酶到达其最终位置，而且为使最终的蛋白酶挤压步骤在能量上变得有利提供了一种绝对必要的偶联机制。因此，F螺旋不是蛋白酶移位的被动障碍，而是使丝氨酸蛋白酶抑制剂抑制机制成功运作的关键活性元件。
