• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.263-268
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• 2003

Recently, we identified a domain, termed MIRC3-4, for the protein-protein interaction between yeast chitin synthase 3 (CHS3) and chitin synthase 4 (CHS4). In this study, the functional roles of MIRC3-4 were examined at the G1 phase and cytokinesis of the cell cycle by Calcofluor staining and FISH. Some mutations in MIRC3-4 resulted in disappearance of the chitin ring in the early G1 phase, but did not affect chitin synthesis in the cell wall at cytokinesis. The chitin distribution in chs4 mutant cells indicated that CHS4 was involved in the synthesis of chitinring in the G1 phase and in the synthesis of cell wall chitin after cytokinesis, suggesting that Chs4p regulates chitin synthase 3 activity differently in G1 and cytokinesis. Absence of the chitin ring could be caused either by delocalization of Chs3p to the bud-neck or by improper interaction with Chs4p. When mutant cells were immunostained with a Chs3p-specific antibody to discriminate between these two alternatives, the mutated Ch3p was found to localize to the neck in all MIRC3-4 mutants. These results strongly irdicate that Chs4p regulates Chs3p as an activator but not a recruiter.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.10a
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• pp.39-45
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• 2000

It hab been proposed that CHS3-mediated chitin synthesis during the vegitative cell cycle is regulated by CHS4. To investigate direct protein-protein interaction between their coding products, we used yeast two hybrid system and found that a domain of Chs3p was responsible for interaction with Chs4p. This domain, termed MIRC3-4 (maximum interacting region of chs3p with chs4p), spans from 647 to 700 residues. It is well conserved among CHS3 homologs of various fungi such as Candida albicans, Emericella nidulans, Neurospora crassa, Magnaporthe grisea, Ustilago maydis, Glomus versiforme, Exophiala dermatitidis, Rhizopus microsporus. A series of mutaion in the MIRC3-4 resulted in no appearance of chitin ring at the early G 1 phase but did not affect chitin synthesis in the cell wall after cytokinesis. Absence of chitin ring could be caused either by delocalization of Chs3p to the septum or by improper interaction with Chs4p. To discriminate those two, not mutually exclusive, alternatives, mutants cells were immunostained with Chs3p-specific antibody. Some exhibited localization of chs3p to the septum, while others failed. These results indicate that simultaneous localization and activation Chs3p by Chs4p is required for chitin ring synthesis.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.60.2-61
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• 2000

No Abstract, See Full Text

• The Plant Pathology Journal
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• v.31 no.1
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• pp.1-11
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• 2015

Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.