報告題目：C-di-GMP, PilZ, and Biofilm

報告時間：2012年6月16日14:00點

報告地點🛣：生物藥學樓3號樓105會議室

報告人：  周三和 教授

國立中興大學生物化學研究所

報告人簡介🏄🏽👨‍👩‍👧‍👧：

周三和教授1976年畢業於臺北師範大學化學系，獲學士學位🤷‍♂️；1978年在臺灣大學獲得生物化學碩士學位；1984年在美國西雅圖華盛頓大學獲化學博士學位🛍️。1984-1996年，在華盛頓大學先後任助教🙍🏼‍♂️，助理教授和副教授🕵🏿‍♂️。1996年至今，在國立中興大學任教授👉🏽，兼任生化研究所所長。周教授實驗室的研究方向包括🙋🏽：結構基因組學🈺，蛋白組學🛩，X-光晶體衍射學。周教授在國內外學術期刊上已經發表了100多篇學術論文，獲得一系列獎勵和榮譽，並擔任多個學術期刊的編委▫️。

報告人網頁🏆： http://biochem.nchu.edu.tw/wb_teacher02.asp?cno=1&tno=58

摘要：

Bacterial type IV pilus (T4P) is a non-flagellar machinery mediating diverse cellular functions, such as surface motility, biofilm formation and pathogenicity. Recent data indicate that T4P biogenesis is initiated via interaction of a non-canonical type II PilZ protein with the FimX and PilB ATPase under high c-di-GMP concentration. However, molecular details of such interactions remain to be elucidated. We now report the hetero-complex crystal structure between a type II PilZ1028 protein and a FimXEAL from Xcc (Xanthomnas campestris pv. campestris) in the presence of c-di-GMP. We demonstrate that c-di-GMP is indispensable for the stable formation of type II XccPilZ1028- XccFimXEAL complex, which is evidenced by a variety of biophysical methods including ITC and gel filtration chromatography. We also show that binding of type II XccPilZ1028 protein induces dimerization of XccFimXEAL domains via a N-terminal helix swapping to form a (XccPilZ1028)2-(XccFimXEAL-c-di-GMP)2 hetero-tetramer complex. In addition, we also observed considerable flexibility for c-di-GMP, which is demonstrated by the discovery of two novel monomeric structures for c-di-GMP  a "bulged" form in the XccFimXEAL-c-di-GMP complex and an "extended but twisted" form in the XccPilZ1028-XccFimXEAL-c-di-GMP complex. Extensive in vitro studies were further carried out using a series of XccPilZ1028 and XccFimXEAL variants to confirm the unique binding modes of c-di-GMP. Altogether, the results represent an important step toward understanding how T4P function is controlled by c-di-GMP in molecular level.