应用^(15)N-~1H残留偶极偶合验证刪除肝癌2(DLC2-SAM)不育-α-基序域的螺旋间的取向(英文)

Validation of Inter-Helical Orientation of the Sterile-α-Motif Domain of the Deleted in Liver Cancer 2(DLC2-SAM) by ^(15)N-~1H Residual Dipolar Couplings

刪除肝癌2(DLC2),一种经常发现在原发性肝癌过低表达的肿瘤抑制基因,编码一种含有不育-α-基序多域蛋白质(DLC2-SAM).以前SAM域蛋白(DLC2-SAM)核磁共振结构显示此蛋白是由独特的四螺旋束组成,与其它已知SAM域结构截然不同.在该研究中,作者运用了15N-1H残留偶极偶合(RDC)作为附加约束连同NOE和TA-LOS数据进一步优化了DLC2-SAM的结构.由此所得的结构与没有15N-1H残留偶极偶合约束比较显示改善了结构的质量并且有较低的Q值.螺旋的取向,尤其是螺旋4,被残留偶极偶合数据所验证.RDC-优化的人类DLC2-SAM的结构与小鼠的DLC2-SAM很相像.DLC家庭独特的SAM域结构表明该域可能还具有没被发现的新功能.

The deleted in liver cancer 2（DLC2）,a tumor suppression gene which is frequently found to be underexpressed in hepatocellular carcinoma,encodes a multi-domain protein comprising a sterile α-motif domain（DLC2-SAM）.Previous NMR structural studies of the SAM domain protein（DLC2-SAM） revealed a unique four helical bundle structure,distinct from any other known SAM domain structures.In the present study,we have applied 15N-1H residual dipolar couplings as additional constraints to refining the solution structures of the DLC2-SAM together with nuclear Overhauser enhancement and TALOS data.The resulting structures show improved quality factors when comparing with the structures derived without RDC constraints and have a lower Q factor.Orientations of the helices,in particular the helix 4,are validated by residual dipolar coupling data.Our RDC-refined human DLC2-SAM structures resemble those of murine DLC2-SAM.The unique structures of the SAM domain from DLC family implicate that the SAM domain may serve novel functions although these have not yet been unveiled.