以可溶性PBP2a为靶点筛选拮抗MRSA中药的实验研究

Screening Anti-MRSA Traditional Chinese Materia Medica by Targeting on Soluble Penicillin Binding Protein 2a

目的以耐甲氧西林金黄色葡萄球菌(MRSA)临床分离株青霉素结合蛋白2a(PBP2a)的可溶性片段为靶点,利用生物传感器筛选能够拮抗MRSA的中药。方法从临床上分离鉴定出MRSA,利用基因重组技术体外诱导表达PBP2a25～668位氨基酸,并对表达的可溶性蛋白进行鉴定及生物学功能分析;然后将PBP2a包被于羧甲基葡聚糖样品池上,利用生物传感器筛选能够拮抗MRSA的中药。结果成功诱导表达出可溶性目的蛋白PBP2a,相对分子质量为74×103,且具有一定的转肽酶及β-内酰胺酶活性;利用生物传感器筛选出10种能够拮抗MRSA的中药,其中黄芩、黄连、夏枯草3种中药抗MRSA作用较强。结论以MRSA临床分离株中可溶性PBP2a为靶点,利用生物传感器成功筛选出了能够拮抗MRSA的中药。

OBJECTIVE To screen the anti-meticillin-resistant Staphylococcus aureus（MRSA）traditional Chinese materia medica（TCMM）by biosensor technique,targeted on the soluble penicillin binding protein 2a（PBP2a）of clinical MRSA.METHODS The soluble PBP2a with amino acid sequence from 25 to 668 from clinical MRSA were expressed in Escherichia coli by gene recombination technique.Then,the expressed product was identified and its biological function was analyzed.After the PBP2a was immobilized into the carboxymethyl dextran cuvette（CMD）,the anti-MRSA TCMM was screened by means of biosensor.RESULTS The soluble protein PBP2a had been successfully expressed,whose relative molecular mass was 74×10^3.It was confirmed that the soluble PBP2a had transpeptidase activitiy and β-lactamase activitiy.Subsequently,10 kinds of anti-MRSA TCMM were screened out by biosensor technique.Moreover,Radix Scutellariae,Rhizoma Coptidis and Spica Prunellae had greater anti-MRSA effect than others.CONCLUSIONS Anti-MRSA TCMM has been successfully screened out by biosensor technique,targeted on the soluble PBP2a of clinical MRSA.