Crystal structure of a bacterial homolog to human lysosomal transporter,spinster

作     者：Fu Zhoua Deqiang Yao Bing Rao Li Zhang Wang Nie Yan Zou Jie Zhao Yu Cao 

作者机构：CAS Center for Excellence on Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai 201210China Institute of Precision MedicineThe Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghai 200125China School of Life Science and TechnologyShanghaiTech UniversityShanghai 201210China Department of OrthopaedicsShanghai Key Laboratory of Orthopaedic ImplantShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghai 200011China 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2019年第64卷第18期

页      面：1310-1317页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Key Research and Development Program of China (2017YFC1001303 and 2018YFC1004704) NSFC-CAS Joint Fund for Research Based on Large-Scale Scientific Facilities (U1632132) NSFC General Program (31670849) SHIPM-pi fund (JY201804) from Shanghai Institute of Precision Medicine, Ninth People’s Hospital Shanghai Jiao Tong University School of Medicine 

主　　题：Major facilitator superfamily Transporter Spinster Membrane protein 

摘      要：Lysosomes break down various biomolecules and spinster is one of the major efflux carriers removing degradation products from lysosomal lumen to keep it in healthy size and proper function.Although it is well established that a dysfunctional spinster will cause enlarged lysosomes and in turn lead to developmental defects and abnormal behavior in animals,little was known about the transportation mechanism and substrate specificity of spinster.Here,we report a crystal structure of spinster homolog from Hyphomonas neptunium,HnSPNS,in its inward-facing conformation with and without substrate bound.HnSPNS is crystallized in a monomer and a substrate-binding cavity was formed in the center of its transmembrane helices.A blob of electron density corresponding to its substrate was found in the cavity near a conserved residue,R42,which is locked in position by the interactions with conserved residues E129 and R122.Our results suggest that human spinster serves as a transporter translocating negativelycharged lipophilic small molecules and E129 might serve as a switch to control the conformational change via its protonation-deprotonation cycle.