2001 Fiscal Year Final Research Report Summary
Sislic acid recognition proteins of Trypanosoma species
| Project/Area Number |
11694291
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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 |
寄生虫学(含医用動物学)
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| Research Institution | Nagasaki University |
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Principal Investigator |
UEMURA Haruki Nagasaki Univ., Inst. of Trop. Med., Assistant Professor, 熱帯医学研究所, 講師 (60184975)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUMA Toshihide Kurume Univ., Kurume Univ. School of Medicine, Professor, 医学部, 教授 (90125146)
KANBARA Hiroji Nagasaki Univ., Inst. of Trop. Med., Professor, 熱帯医学研究所, 教授 (20029789)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Trypanosoma / Trans-sialidase / South American Chagas' disease / African sleeping sickness / Sialic acid / Gene family / Protein purification |
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| Research Abstract |
The unique enzyme of some infective Trypanosoma species, trans-sialidase catalyzes the sialic acid transfer reactions from host derived glycoconjugates to the parasite surface mucinlike acceptor molecules and vice versa. Several lines of evidence have suggested that trans-sialidase and sialylated molecules on the parasite and host cell surface are important for parasite invasion to the host cells and escape from host defense systems. We have investigated the functional analysis of trans-sialidase in molecular level.
In this study, we have successfully purified and characterized trans-sialidase obtained from the culture medium of Trypanosome brucei, which causes African sleeping sickness. This enzyme showed several biochemical similarities to that of Trypanosoma cruzi, which is the etiological agent of Chagas' disease. We also have expressed and purified homogeneously the recombinant trans-sialidase of T. cruzi using bacterial expression system. These enzymes are used for the recognition studies of the parasite protein by host cells. The comparison of enzymatically active and inactive forms of purified recombinant proteins were important for understanding the function of trans-sialidase activitis.
We have obtained and analyzed several T. cruzi trans-sialidase genes expressed in trypomastigote and epimastigote stages of this parasite. The enzyme expressed in infective trypomastigote stage (T-TS) is located on the parasite surface through a glycosyl phosphatididylinositol (GPI) anchor, and readily shed into culture supernatant in vitro and into the bloodstream of animals in vivo. On the other hands, trans-sialidase of noninfective epimastigote stage is not released into the medium nor recognized by antibodies against the carboxyl terminal repeats of T-TS.
We have sequences these family genes to understand functions, molecular mechanisms of expression and localization of these two different types of trans-sialidases.
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