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| [[Image:1bfa.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1bfa| PDB=1bfa | SCENE= }} | | {{STRUCTURE_1bfa| PDB=1bfa | SCENE= }} |
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| '''RECOMBINANT BIFUNCTIONAL HAGEMAN FACTOR/AMYLASE INHIBITOR FROM MAIZE'''
| | ===RECOMBINANT BIFUNCTIONAL HAGEMAN FACTOR/AMYLASE INHIBITOR FROM MAIZE=== |
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| ==Overview==
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| Corn Hageman factor inhibitor (CHFI) is a bifunctional 127 residue, 13.6 kDa protein isolated from corn seeds. It inhibits mammalian trypsin and Factor XIIa (Hageman Factor) of the contact pathway of coagulation as well as alpha-amylases from several insect species. Among the plasma proteinases, CHFI specifically inhibits Factor XIIa without affecting the activity of other coagulation proteinases. We have isolated CHFI from corn and determined the crystallographic structure at 1.95 A resolution. Additionally, we have solved the structure of the recombinant protein produced in Escherichia coli at 2.2 A resolution. The two proteins are essentially identical. The proteinase binding loop is in the canonical conformation for proteinase inhibitors. In an effort to understand alpha-amylase inhibition by members of the family of 25 cereal trypsin/alpha-amylase inhibitors, we have made three-dimensional models of several proteins in the family based on the CHFI coordinates and the coordinates determined for wheat alpha-amylase inhibitor 0.19 [Oda, Y., Matsunaga, T., Fukuyama, K., Miyazaki, T., and Morimoto, T. (1997) Biochemistry 36, 13503-13511]. From an analysis of the models and a structure-based sequence analysis, we propose a testable hypothesis for the regions of these proteins which bind alpha-amylase. In the course of the investigations, we have found that the cereal trypsin/alpha-amylase inhibitor family is evolutionarily related to the family of nonspecific lipid-transfer proteins of plants. This is a new addition to the group which now consists of the trypsin/alpha-amylase inhibitors, 2S seed storage albumins, and the lipid-transfer family. Apparently, the four-helix conformation has been a successful vehicle in plant evolution for providing protection from predators, food for the embryo, and lipid transfer.
| | The line below this paragraph, {{ABSTRACT_PUBMED_9799488}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 9799488 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_9799488}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Amylase/protease bifunctional inhibitor]] | | [[Category: Amylase/protease bifunctional inhibitor]] |
| [[Category: Serine protease inhibitor]] | | [[Category: Serine protease inhibitor]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 11:26:21 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 19:01:33 2008'' |