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From Proteopedia
Crystal structure of the zymogen catalytic region of human MASP-2
Structural highlights
Disease[MASP2_HUMAN] Defects in MASP2 are the cause of MASP2 deficiency (MASPD) [MIM:613791]. MASPD is a disorder that results in autoimmune manifestations, recurrent severe infections, and chronic inflammatory disease.[1] [2] Function[MASP2_HUMAN] Serum protease that plays an important role in the activation of the complement system via mannose-binding lectin. After activation by auto-catalytic cleavage it cleaves C2 and C4, leading to their activation and to the formation of C3 convertase.[3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedFew reports have described in detail a true autoactivation process, where no extrinsic cleavage factors are required to initiate the autoactivation of a zymogen. Herein, we provide structural and mechanistic insight into the autoactivation of a multidomain serine protease: mannose-binding lectin-associated serine protease-2 (MASP-2), the first enzymatic component in the lectin pathway of complement activation. We characterized the proenzyme form of a MASP-2 catalytic fragment encompassing its C-terminal three domains and solved its crystal structure at 2.4 A resolution. Surprisingly, zymogen MASP-2 is capable of cleaving its natural substrate C4, with an efficiency about 10% that of active MASP-2. Comparison of the zymogen and active structures of MASP-2 reveals that, in addition to the activation domain, other loops of the serine protease domain undergo significant conformational changes. This additional flexibility could play a key role in the transition of zymogen MASP-2 into a proteolytically active form. Based on the three-dimensional structures of proenzyme and active MASP-2 catalytic fragments, we present model for the active zymogen MASP-2 complex and propose a mechanism for the autoactivation process. A true autoactivating enzyme. Structural insight into mannose-binding lectin-associated serine protease-2 activations.,Gal P, Harmat V, Kocsis A, Bian T, Barna L, Ambrus G, Vegh B, Balczer J, Sim RB, Naray-Szabo G, Zavodszky P J Biol Chem. 2005 Sep 30;280(39):33435-44. Epub 2005 Jul 21. PMID:16040602[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Ambrus, G | Balczer, J | Barna, L | Bian, T | Gal, P | Harmat, V | Kocsis, A | Naray-Szabo, G | Sim, R B | Vegh, B | Zavodszky, P | Beta barrel | Hydrolase | Modular protein
