title: Structural basis for broad substrate specificity of earthworm fibrinolytic enzyme component A.
abstract: Earthworm fibrinolytic enzyme component A (EFE-a) possesses an S1 pocket, which is typical for an elastase-like enzyme, but it can still hydrolyze varieties of substrates, and it exhibits wide substrate specificity. Former structure studies suggested that the four-residue insertion after Val(217) might endow EFE-a with this specificity. Based on the native crystal structure at a resolution of 2.3A, we improved the native crystal structure to 1.8A and determined its complex structure with the inhibitor Meo-Suc-Ala-Ala-Pro-Val-CMK at a resolution of 1.9A. The final structures show that: (1) EFE-a possesses multisubstrate-binding sites interacting with the substrates; (2) significant conformation adjustment takes place at two loops binding to the N-terminal of the substrates, which may enhance the interaction between the enzyme and the substrates. These characteristics make the substrate-specificity of EFE-a less dependent on the property of its S1-pocket and may endow the enzyme with the ability to hydrolyze chymotrypsin-specific substrates and even trypsin-specific substrates.
authors.affiliation: National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang
authors.forename: Ji-Ping
authors.initials: JP
authors.lastname: Zhang
authors.forename: Lu-Lu
authors.initials: LL
authors.lastname: Gui
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: An
authors.forename: Wen-Rui
authors.initials: WR
authors.lastname: Chang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002384:Catalysis; D003198:Computer Simulation; D010450:Endopeptidases / Q000032:analysis / Q000737:chemistry*; D004789:Enzyme Activation; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry; D009835:Oligochaeta / Q000201:enzymology*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D046912:Multiprotein Complexes; D010450:Endopeptidases; C083421:lumbrokinase