Premium
Structure of the ribosome associating GTPase HflX
Author(s) -
Wu Hao,
Sun Lei,
Blombach Fabian,
Brouns Stan J.J.,
Snijders Ambrosius P. L.,
Lorenzen Kristina,
van den Heuvel Robert H. H.,
Heck Albert J. R.,
Fu Sheng,
Li Xuemei,
Zhang Xuejun C.,
Rao Zihe,
van der Oost John
Publication year - 2009
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.22599
Subject(s) - gtpase , sulfolobus solfataricus , cyclic nucleotide binding domain , coiled coil , ribosome , guanosine triphosphate , protein subunit , biology , guanosine , gtp' , binding domain , microbiology and biotechnology , biophysics , chemistry , nucleotide , biochemistry , binding site , rna , enzyme , gene , archaea
The HflX‐family is a widely distributed but poorly characterized family of translation factor‐related guanosine triphosphatases (GTPases) that interact with the large ribosomal subunit. This study describes the crystal structure of HflX from Sulfolobus solfataricus solved to 2.0‐Å resolution in apo‐ and GDP‐bound forms. The enzyme displays a two‐domain architecture with a novel “HflX domain” at the N‐terminus, and a classical G‐domain at the C‐terminus. The HflX domain is composed of a four‐stranded parallel β‐sheet flanked by two α‐helices on either side, and an anti‐parallel coiled coil of two long α‐helices that lead to the G‐domain. The cleft between the two domains accommodates the nucleotide binding site as well as the switch II region, which mediates interactions between the two domains. Conformational changes of the switch regions are therefore anticipated to reposition the HflX‐domain upon GTP‐binding. Slow GTPase activity has been confirmed, with an HflX domain deletion mutant exhibiting a 24‐fold enhanced turnover rate, suggesting a regulatory role for the HflX domain. The conserved positively charged surface patches of the HflX‐domain may mediate interaction with the large ribosomal subunit. The present study provides a structural basis to uncover the functional role of this GTPases family whose function is largely unknown. Proteins 2010. © 2009 Wiley‐Liss, Inc.