RRC ID 34495
Author Fukuda M, Takeda H, Kato HE, Doki S, Ito K, Maturana AD, Ishitani R, Nureki O.
Title Structural basis for dynamic mechanism of nitrate/nitrite antiport by NarK.
Journal Nat Commun
Abstract NarK belongs to the nitrate/nitrite porter (NNP) family in the major facilitator superfamily (MFS) and plays a central role in nitrate uptake across the membrane in diverse organisms, including archaea, bacteria, fungi and plants. Although previous studies provided insight into the overall structure and the substrate recognition of NarK, its molecular mechanism, including the driving force for nitrate transport, remained elusive. Here we demonstrate that NarK is a nitrate/nitrite antiporter, using an in vitro reconstituted system. Furthermore, we present the high-resolution crystal structures of NarK from Escherichia coli in the nitrate-bound occluded, nitrate-bound inward-open and apo inward-open states. The integrated structural, functional and computational analyses reveal the nitrate/nitrite antiport mechanism of NarK, in which substrate recognition is coupled to the transport cycle by the concomitant movement of the transmembrane helices and the key tyrosine and arginine residues in the substrate-binding site.
Volume 6
Pages 7097
Published 2015-5-11
DOI 10.1038/ncomms8097
PII ncomms8097
PMID 25959928
PMC PMC4432589
MeSH Anion Transport Proteins / genetics Anion Transport Proteins / metabolism* Binding Sites Cloning, Molecular Escherichia coli / genetics Escherichia coli / metabolism* Gene Expression Regulation, Bacterial / physiology Liposomes Models, Molecular Nitrate Transporters Nitrates / metabolism* Nitrites / metabolism* Protein Binding Protein Conformation
IF 12.121
Times Cited 19
DNA material Genomic DNA of Escherichia coli JCM 20135 (JGD07547)
General Microbes