2005 Fiscal Year Final Research Report Summary
Universality analysis of D-amino acid biosystem in aquatic invertebrates
| Project/Area Number |
16380141
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fisheries chemistry
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ABE Hiroki The university of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (80086727)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Shigeru The university of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (00224014)
YOSHIKAWA Naoko The university of Tokyo, Graduate School of Agricultural and Life Sciences, Assistant, 大学院・農学生命科学研究科, 助手 (30392533)
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| Project Period (FY) |
2004 – 2005
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| Keywords | D-amino acid / D-alanine / D-aspartic acid / alanine racemase / aspartate racemase / invertebrate / isosmotic regulation / nervous system |
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| Research Abstract |
The objective of this research is to clarify the universality of ‘D-amino acid biosystem' in which free D-amino acids distributed widely in invertebrates play important roles in aquatic invertebrates.
1.Based on the alanine racemase (ARase) cDNA obtained from the muscle and hepatopancreas of the kuruma prawn, ARase protein was overexpressed from E.coli cells, purified, and characterized. Novel ARase cDNA sequence was also compared with that of the known one. The sequence showed some sequence deficits in the 5' upper region of open reading frame.
2.An ARase cDNA was cloned from the mid-gut gland of otter shell that has a large amount of D-alanine in muscle tissues. The deduced amino acid sequence displayed only 32 % amino acid identity with that of the prawn, which was only slightly high with that of microbes. Otter shell ARase was overexpressed from E.coli cells, purified to homogeneity, and confirmed its activity.
3.Aspartate racemase (DRase) acitivity was determined on the tissues of ar
… More
k shells and cephalopods that have no D-alanine but a significant amount of D-aspartate. A DRase cDNA was cloned from the optic lobes of common flying squid. The deduced amino acid sequence showed 48% amino acid identity with that of ark shell but just below 40% with that of serine racemase in mammalian brain and threonine dehydratase in microbes. The sequence showed no homology to bacterial DRase. As these enzymes are all PLP-dependent, these data are very important to clarify the molecular evolutional process of these enzymes.
4.Distribution of D-alanine and ARase was examined on various polychaetes and revealed the existence only in a group of polychaetes. During the acclimation of a polychaete from 15 to 41 ppt seawater, only D- and L-alanine increased largely in the body walls, suggesting the role of D-alanine as an osmolyte responsible for the isosmotic regulation. cDNA cloning from the polychaete is now in progress.
These results indicate that ‘D-amino acid biosystem' is universally operating in crustaceans, mollusks, and polychaetes. Less
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Research Products
(14 results)
