Journal article
Sequences required for thrombomodulin cofactor activity within the fourth epidermal growth factor-like domain of human thrombomodulin
The Journal of biological chemistry, Vol.268(20), pp.15312-15317
1993
DOI: 10.1016/S0021-9258(18)82471-1
PMID: 8392074
Abstract
Activation of protein C by thrombin is stimulated by the endothelial cell cofactor thrombomodulin. The structural regions of thrombomodulin necessary for cofactor activity have been localized to the fourth through sixth epidermal growth factor (EGF)-like domains. The fourth EGF-like domain is unnecessary for high affinity thrombin binding, but is required for cofactor activity. To identify essential sequences within the fourth EGF-like domain, a series of recombinant human thrombomodulins consisting of EGF-like domains four through six were expressed in human kidney cells. These mutants contain replacements of disulfide loops within the fourth EGF-like domain, thereby conserving overall disulfide bond structure. All of the mutants bound to thrombin with high affinity, and inhibited the fibrinogen-clotting activity of thrombin to a similar extent. Two regions of the fourth EGF-like domain were identified to be essential for cofactor activity: 1) the sequence consisting of amino acids Glu-357, Tyr-358, and Gln-359 shared by the overlapping first and second disulfide loops, and 2) the amino-terminal region of the third disulfide loop containing amino acids Glu-374, Gly-375, and Phe-376. These results suggest that amino acids critical for thrombomodulin cofactor activity are located near the junction between the two subdomains of the fourth EGF-like domain.
Details
- Title: Subtitle
- Sequences required for thrombomodulin cofactor activity within the fourth epidermal growth factor-like domain of human thrombomodulin
- Creators
- Steven R Lentz - Univ. Iowa, dep. internal medicine, Iowa City IA 52242, United StatesYan Chen - Univ. Iowa, dep. internal medicine, Iowa City IA 52242, United StatesJ Evan Sadler - Univ. Iowa, dep. internal medicine, Iowa City IA 52242, United States
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.268(20), pp.15312-15317
- DOI
- 10.1016/S0021-9258(18)82471-1
- PMID
- 8392074
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Publisher
- American Society for Biochemistry and Molecular Biology
- Language
- English
- Date published
- 1993
- Academic Unit
- Hematology, Oncology, and Blood & Marrow Transplantation; Internal Medicine
- Record Identifier
- 9984094666202771
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