Crystal Structure of Earthworm Fibrinolytic Enzyme Component B: a Novel, Glycosylated Two-chained Trypsin

The earthworm fibrinolytic enzyme (EFE), belonging to a group of serine proteases with strong fibrinolytic activity, has been used in a mixture as an oral drug for prevention and treatment of thrombosis in East Asia. The EFE component b (EFE-b) is one of seven EFE components from Eisenia fetida, and...

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Bibliographic Details
Published in:Journal of molecular biology 2005-05, Vol.348 (3), p.671-685
Main Authors: Wang, Feng, Wang, Chao, Li, Mei, Zhang, Ji-Ping, Gui, Lu-Lu, An, Xiao-Min, Chang, Wen-Rui
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Binding Sites
Calcium - metabolism
crystal structure
Crystallography, X-Ray
earthworm fibrinolytic enzyme
eight-membered ring
Endopeptidases - chemistry
Endopeptidases - genetics
Enzyme Stability
Glycosylation
Models, Molecular
Molecular Sequence Data
N-glycosylation
Oligochaeta - enzymology
Protein Precursors - genetics
Protein Structure, Quaternary
Protein Structure, Tertiary
Sequence Alignment
stability
Trypsin - chemistry
Trypsin - genetics
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Summary:The earthworm fibrinolytic enzyme (EFE), belonging to a group of serine proteases with strong fibrinolytic activity, has been used in a mixture as an oral drug for prevention and treatment of thrombosis in East Asia. The EFE component b (EFE-b) is one of seven EFE components from Eisenia fetida, and among them it has nearly the highest fibrinolytic activity. Here, we report its crystal structure at a resolution of 2.06 Å. The structural analysis shows that EFE-b should be classified as a trypsin from earthworm. However, it is distinct from other trypsins. It is a two-chained protease with an N-terminal, pyroglutamated light chain and an N-glycosylated heavy chain. Furthermore, the heavy chain contains a novel structural motif, an eight-membered ring resulting from a disulfide bridge between two neighboring cysteine residues, and a cis peptide bond exists between these two cysteine residues. The crystal structure of EFE-b provides the structural basis for its high level of stability and reveals its complicated post-translational modifications in earthworm. This structure is the first reported for a glycosylated two-chained trypsin, which may provide useful clues to explain the origin and evolution of the chymotrypsin family.
ISSN:0022-2836
1089-8638
DOI:10.1016/j.jmb.2005.02.055