Structural highlights
Function
NAH1_METJA This is a Na(+)/H(+) antiporter. Can also transport lithium.[1]
Publication Abstract from PubMed
Sodium/proton antiporters are essential for sodium and pH homeostasis and play a major role in human health and disease. We determined the structures of the archaeal sodium/proton antiporter MjNhaP1 in two complementary states. The inward-open state was obtained by x-ray crystallography in the presence of sodium at pH8, where the transporter is highly active. The outward-open state was obtained by electron crystallography without sodium at pH4, where MjNhaP1 is inactive. Comparison of both structures reveals a 7{degree sign} tilt of the 6 helix bundle. 22Na+ uptake measurements indicate non-cooperative transport with an activity maximum at pH7.5. We conclude that binding of a Na+ ion from the outside induces helix movements that close the extracellular cavity, open the cytoplasmic funnel, and result in a ~5 A vertical relocation of the ion binding site to release the substrate ion into the cytoplasm.
Structure and transport mechanism of the sodium/protonantiporter MjNhaP1.,Paulino C, Wohlert D, Kapotova E, Yildiz O, Kuhlbrandt W Elife. 2014 Nov 26;3. doi: 10.7554/eLife.03583. PMID:25426803[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hellmer J, Patzold R, Zeilinger C. Identification of a pH regulated Na(+)/H(+) antiporter of Methanococcus jannaschii. FEBS Lett. 2002 Sep 11;527(1-3):245-9. PMID:12220668
- ↑ Paulino C, Wohlert D, Kapotova E, Yildiz O, Kuhlbrandt W. Structure and transport mechanism of the sodium/protonantiporter MjNhaP1. Elife. 2014 Nov 26;3. doi: 10.7554/eLife.03583. PMID:25426803 doi:http://dx.doi.org/10.7554/eLife.03583