Mechanism of automutanolysin conferring substrate selectivity on cariogenic streptococci

• Project/Area Number: 23592702
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Morphological basic dentistry
• Research Institution: Hiroshima University
• Principal Investigator: HAYASHI Ikue 広島大学, 医歯薬保健学研究院, 助教 (00346503)
• Co-Investigator(Kenkyū-buntansha): OHARA Masaru 広島大学, 病院, 助教 (80253095) ; KATOU Fuminori 広島大学, 医歯薬保健学研究院, 助教 (70452589)
• Co-Investigator(Renkei-kenkyūsha): SUGAI Motoyuki 広島大学, 医歯薬保健学研究院, 教授 (10201568)
• Research Collaborator: THANYASRISUNG Panida 広島大学, 医歯薬保健学研究院, 留学生
• Project Period (FY): 2011 – 2013
• Project Status: Completed (Fiscal Year 2013)
• Budget Amount: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000); Fiscal Year 2013: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2012: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2011: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: 溶菌酵素 / ペプチドグリカン / 基質特異性 / 口腔レンサ球菌 / う喰

Research Abstract

Automutanolysin (Aml) produced by S.mutans selectively lyses S. mutans and S. sobrinus but not other oral streptococci. To unveil the mechanism how Aml draws this distinction, we analysed the peptidoglycan structures of oral streptococci. We made various recombinant Aml. It consists of two domains: a C-terminal catalytic domain and an N-terminus containing five repeats presumably acting as a cell wall targeting domain. A full length of targeting domain revealed the highest binding ability to the tested strain. Moreover, it clearly distinguished cariogenic bacteria from other oral streptococci. Comparison of the muropeptide profiles of oral streptococci strains with different level of susceptibility to Aml appeared to be correlated with ratio of muropeptides carrying a Penta-peptide chain for Aml resistance. Binding domain of Aml clearly differentiate cariogenic streptococci from others by recognizing peptidoglycan structure.

Research Products

• [Journal Article] The Listeria monocytogenes serotype 4b autolysin IspC has N-acetylglucosaminidase activity (2012)
  • Author(s): Ronholm J., Wang L., Hayashi I., Sugai M., Zhang Z., Cao X., Lin M.
  • Journal Title: Glycobiology Volume: 22(10) Pages: 1311-1320
• [Presentation] The N-terminal cell wall targeting domain of automutanolysin confers substrate selectivity on cariogenic streptococci (2013)
  • Author(s): P. Thanyasrisung, I. Hayashi, T. Fujiwara, K. Tsuruda, M. Sugai
  • Organizer: 2^<nd> Meeting of the International Association for Dental Research–Asia Pacific Region
  • Place of Presentation: Bangkok
• [Presentation] The N-terminal cell wall targeting domain of automutanolysin confers substrate selectivity on cariogenic streptococci (2013)
  • Author(s): P Thanyasrisung, I. Hayashi, T. Fujiwara, K.Tsuruda, M.Sugai
  • Organizer: 2nd Meeting of the International Association for Dental Research
  • Place of Presentation: Bangkok、Thailand