1990 Fiscal Year Final Research Report Summary
Phylogenetic Comparison of Protein and Gene Structures of a Bactericidal Factor, RaRF
| Project/Area Number |
63570200
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | Kitasato University |
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Principal Investigator |
KAWAKAMI Masaya Kitasato Univ. Sch. Med. Professor, 医学部, 教授 (50050349)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Kunie Kitasato Univ. Sch. Med. Associate Professor, 医学部, 助教授 (00118829)
IHARA Setsunosuke Kitasato Univ. Sch. Med. Associate Professor, 医学部, 助教授 (90101295)
TAKAHASHI Akiyoshi Kitasato Univ. Sch. Med. Research Associate, 医学部, 助手 (10183849)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Primary structure / cDNA / Complement / Bactericidal / Serum protein / Enterobacteria / Phylogeny / Lipopolysaccharide |
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| Research Abstract |
Ra-reactive factor (RaRF) is a complement-dependent bactericidal factor which have been found by us in sera of a wide variety of vertebrates. It binds specifically to a polysaccharide common to enterobacteria such as Salmonella and certain strains of Escherichia coli. Results of recent studies indicate that mouse RaRF is a lectin resembling the C1 component of complement, since it activates the C4 and C2 components of complement by the way similar to the C1, after specific binding to the Ra polysaccharide. Mouse RaRF is a protein complex composed of a polysaccharide-binding component and a serine protease component which activates C4 and C2. Therefore, it resembles C1 not only its function but also structure. Primary structures of component polypeptides of RaRF were determined by their partial amino acid sequences and cDNA base sequences.
It was found that the activity of RaRF is present in representative species of vertebrates, birds, reptiles, amphibians, and fishes. Certain characteristics such as binding specificity to the Ra determinant, requirement of divalent cations are shared by these factors, and apparent molecular weights 290-300k) are similar in vertebrate RaRFs. Molecular weight and antigenicity of a component of chicken RaRF have homology with those of mouse RaRF. Furthermore, a cDNA found in bullfrog liver had a base sequence homology to that of mouse RaRF component. These results indicate that the RaRF have been conserved for more than 300 million years as a result of the necessity for the resistance to roughmutants of Gram-negative enterobacteria.
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Research Products
(22 results)
