The refined 1.9 A crystal structure of human α-thrombin: interaction with D-Phe-Pro-Arg-chloromethylketone and significance of the Tyr-Pro-Pro-Trp insertion segment - Bode, W; Mayr, I; Baumann, U; Huber, R; Stone, S R; Hofsteenge, J (Embo J, 1989)