[3P-1] ポスター3（3P-01ー3P-47）

[3P-04] セラミド輸送蛋白質CERTがクラミジア封入体の膜蛋白質IncDに選択的にハイジャックされる分子機序の溶液NMR解析

^○杉木 俊彦¹, 熊谷 圭悟², 新家 粧子¹, 小林 直宏¹, 藤原 敏道¹, 花田 賢太郎², 児嶋 長次郎^1,3 (1.阪大・蛋白研, 2.国立感染研・細胞化学, 3.横浜国大院・工)

In mammalian cells, the ceramide transport protein (CERT) transports ceramide from the endoplasmic reticulum (ER) to the Golgi apparatus. Human CERT is essential for the obligate intracellular bacterium Chlamydia trachomatis to proliferate in human cells. C. trachomatis forms a vacuole named "inclusion", in which it replicates. The inclusion-resident membrane protein IncD recruits CERT to the inclusion by binding to the CERT PH domain, thereby redirecting host ceramide from the ER to the inclusion. The PH domain of OSBP, an oxysterol-transfer protein, is not recognized by IncD although its primary sequence is highly similar to that of the CERT PH domain. We here explored how IncD specifically recognizes the CERT PH domain by solution NMR experiments. We first determined the tertiary structure of the OSBP PH domain. Then, to identify amino acid residues of the CERT PH domain that specifically participate in interaction with IncD, we performed a comparative analysis about chemical shift perturbation of the CERT PH and the OSBP PH domains by titrating a recombinant soluble IncD. Its results revealed that IncD captures specific sites of the surface of the CERT PH domain in a tweezer-like manner.