Faculty

	조홍백 (Hongbaek Cho)
	직함	부교수
	전공	미생물학
	연구실	미생물학연구실
	전화	031-299-4498
	사무실	제2과학관 32208
	이메일	hongbaek@skku.edu

Research Background

We are facing a global problem with the rise of antibiotic resistant infections. New therapies to combat antibiotic-resistant pathogens are sorely needed to avoid a post-antibiotic crisis. Simple screening for compounds that show antimicrobial activities is not likely to yield many new therapies because exhaustive drug screening programs have already been performed. Therefore, novel approaches inspired by the comprehensive understanding of cellular processes are required to make breakthroughs in antibiotic development.

A better understanding of bacterial cell envelope biogenesis is especially important in this regard because: 1) the bacterial cell envelope is an excellent drug target as it is an essential structure unique to prokaryotes and 2) many antibiotic resistance mechanisms require a properly functioning cell envelope. Thus, study of bacterial envelope biogenesis can reveal novel targets for antibiotic development and provide new ways to disrupt this structure for enhancing the efficacy of existing antibiotics.

My current research interest is focused on the biogenesis of the bacterial cell envelope. Although there has been significant progress in the understanding of how this multilayered structure is assembled, some of the most basic questions are still not satisfactorily answered. One such question is which enzymes are responsible for the synthesis of the bacterial cell wall, the load-bearing structure of the cell envelope. My recent work suggests that bacterial cell wall synthesis is promoted by two types of polymerase systems rather than by a single type of polymerases as currently believed, necessitating a major change in our view of bacterial cell wall assembly. How the activities of these two systems are coordinated for proper cell wall assembly requires intense investigation and is one of the research focuses of my lab. Another big research question I want to pursue is how bacteria maintain the integrity of the cell wall while constantly remodeling its structure for cell growth. To achieve these seemingly contradictory functions, cell wall synthetic activities should be meticulously coordinated with the cell wall hydrolytic activities that cleave the cell wall matrix to allow its expansion. I am also going to extend my research towards studying how cell wall assembly is coordinated with the biogenesis of other structures of the cell envelope, such as the outer membrane that surrounds the cell wall and functions as a permeability barrier against antimicrobial compounds. Ultimately, my research aims to provide useful information on how to disrupt these processes for antibiotic development.

Peer review paper

To view the latest publication list of Hongbaek Cho,

Visit  https://www.ncbi.nlm.nih.gov/pubmed/?term=Hongbaek+Cho

1. Buss JA, Baidin V, Welsh MA, Flores-Kim J, Cho H, Wood BM, Uehara T, Walker S, Kahne D, Bernhardt TG. 2019. Pathway-Directed Screen for Inhibitors of the Bacterial Cell Elongation Machinery. Antimicrob. Agents Chemother. 63:e01530-18

2. Rohs PDA, Buss J, Sim SI, Squyres GR, Srisuknimit V, Smith M, Cho H, Sjodt M, Kruse AC, Garner EC, Walker S, Kahne DE, Bernhardt TG. 2018. A central role for PBP2 in the activation of peptidoglycan polymerization by the bacterial cell elongation machinery. PLoS Genet. 14:e1007726

3. Chamakura, K.R., Sham, L.T., Davis, R.M., Min, L., Cho, H., Ruiz, N, Bernhardt, T.G., Young, R. 2017. A viral protein antibiotic inhibits lipid II flippase activity. Nature Microbiol. 2:1480 

4. Lai, G.C.*, Cho, H.*†, and Bernhardt, T.G.† 2017. The mecillinam resistome reveals a role for peptidoglycan endopeptidases in stimulating cell wall synthesis in Escherichia coli. PLoS Genet. 13 (7):e1006934 *(co-first author) †(co-corresponding author) 

5. Cho, H.*, Wivagg C.N.*, Kapoor, M.*, Barry, Z.T., Rohs, P.D.A., Suh H., Marto J., Garner, E.C., and Bernhardt, T.G. 2016.  Bacterial cell wall biogenesis is mediated by SEDS and PBP polymerase families functioning semi-autonomously. Nature Microbiol. 1: 16172. *(co-first author) 

Elected as one of the best 10 papers in Nature Microbiology (2016)

http://sci.scientific-direct.net/view_online.asp?1410077&24ea4bafc9c6226c&18

6. Yunck, R., Cho, H., and Bernhardt, T.G. 2016.  Identification of MltG as a potential terminase for peptidoglycan polymerization in bacteria. Mol. Microbiol. 99 (4): 700-718. 

7. Cho, H. 2015.  The role of cytoskeletal elements in shaping bacterial cells. J. Microbiol. Biotechnol. 25 (3): 307-316 

8. Cho, H., Uehara, T., and Bernhardt T.G. 2014.  Beta-lactam antibiotics induce a lethal malfunctioning of the bacterial cell wall synthesis machinery. Cell 159 (6): 1300-1311. 

9. Cho, H. and Bernhardt, T.G. 2013.  Identification of the SlmA active site responsible for blocking bacterial cytokinetic ring assembly over the chromosome. PLoS Genet. 9 (2): e1003304. 

10. Cho, H., MacManus, H.R., Dove, S.L., and Bernhardt, T.G. 2011. Nucleoid occlusion factor SlmA is a DNA-activated FtsZ polymerization antagonist.  Proc. Natl. Acad. Sci. USA 108: 3773-3778. 

11. Costa, E.D., Cho, H., and Winans, S.C. 2009.  Identification of amino acid residues of the pheromone-binding domain of the transcription factor TraR that are required for positive control. Mol. Microbiol. 73: 341-351. 

12. Cho, H*. Pinto, U.M*., and Winans S.C. 2009. Transsexuality in the rhizosphere: quorum sensing reversibly converts Agrobacterium tumefaciens from phenotypically female to male.  J. Bacteriol. 191:3375-3383. *(co-first author) 

13. Cho, H. and Winans, S.C. 2007. TraC and TraD elevate the efficiency of Ti plasmid transfer and repress the expression from the divergent promoters near oriT with cis-acting TraA.  Mol. Microbiol.  63: 1769-1782. 

14. Chai, Y., Tsai, C., Cho, H., and Winans S.C.  2007. Reconstitution of the biochemical activities of the AttJ repressor and the AttK, AttL, and AttM catabolic enzymes of Agrobacterium tumefaciens.  J. Bacteriol. 189: 3674-3679. 

15. Cho, H. and Winans, S.C. 2005. VirA and VirG activate the Ti plasmid repABC operon, elevating plasmid copy number in response to wound-released chemical signals.  Proc. Natl. Acad. Sci. USA 102: 14843-14848.

16. Weingart, C., White, C., Liu, S., Chai, Y., Cho, H., Tsai, C., Wei, Y., Delay, N.R., Eberhard, A., and Winans, S.C. 2005. Direct binding of the quorum-sensing regulator CepR of Burkholderia cenocepacia to two target promoters in vitro.  Mol. Microbiol. 57: 452-467.

Funding history

• 2019.3 - 2022.2    중견연구, 한국연구재단 (NRF)

Education and experiences

	권오현
	과정	석박통합과정
	연구실	미생물학연구실(제2과학관 32207호)
	전화	031-299-4507
	이메일	kinkin67@g.skku.edu

	전욱종
	과정	석박통합과정
	연구실	미생물학연구실(제2과학관 32207호)
	전화	031-299-4507
	이메일	finalfate@naver.com

	이남주
	과정	학부연구생
	연구실	미생물학연구실(제2과학관 32207호)
	전화	031-299-4507
	이메일	wuop3k@g.skku.edu