bioinformatics and structural characterization of a hypothetical protein from streptococcus mutans implication of antibiotic resistance假设蛋白的生物信息学和结构表征变形链球菌抗生素耐药性的影响.pdf

Bioinformatics and Structural Characterization of a Hypothetical Protein from Streptococcus mutans: Implication of Antibiotic Resistance 1. 1. 1 3 1,2 Jie Nan , Erik Brostromer , Xiang-Yu Liu , Ole Kristensen , Xiao-Dong Su * 1 National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, People’s Republic of China, 2 Shenzhen Graduate School of Peking University, Shenzhen, People’s Republic of China, 3 University of Copenhagen, Faculty of Pharmaceutical Sciences, Copenhagen, Denmark Abstract As an oral bacterial pathogen, Streptococcus mutans has been known as the aetiologic agent of human dental caries. Among a total of 1960 identified proteins within the genome of this organism, there are about 500 without any known functions. One of these proteins, SMU.440, has very few homologs in the current protein databases and it does not fall into any protein functional families. Phylogenetic studies showed that SMU.440 is related to a particular ecological niche and conserved specifically in some oral pathogens, due to lateral gene transfer. The co-occurrence of a MarR protein within the same operon among these oral pathogens suggests that SMU.440 may be associated with antibiotic resistance. The structure determination of SMU.440 revealed that it shares the same fold and a similar pocket as polyketide cyclases, which indicated that it is very likely to bind some polyketide-like molecules. From the interlinking structural and bioinformatics studies, we have concluded that SMU.440 could be involved in polyketide-like antibiotic resistance, providing a better understanding of this hypothetical protein. Be