Structural highlights
Function
[HPPA_THEMA] Sodium pump that utilizes the energy of pyrophosphate hydrolysis as the driving force for Na(+) movement across the membrane.[HAMAP-Rule:MF_01129][1] [2] [3]
Publication Abstract from PubMed
Membrane-integral pyrophosphatases (M-PPases) are crucial for the survival of plants, bacteria, and protozoan parasites. They couple pyrophosphate hydrolysis or synthesis to Na(+) or H(+) pumping. The 2.6-angstrom structure of Thermotoga maritima M-PPase in the resting state reveals a previously unknown solution for ion pumping. The hydrolytic center, 20 angstroms above the membrane, is coupled to the gate formed by the conserved Asp(243), Glu(246), and Lys(707) by an unusual "coupling funnel" of six alpha helices. Comparison with our 4.0-angstrom resolution structure of the product complex suggests that helix 12 slides down upon substrate binding to open the gate by a simple binding-change mechanism. Below the gate, four helices form the exit channel. Superimposing helices 3 to 6, 9 to 12, and 13 to 16 suggests that M-PPases arose through gene triplication.
The structure and catalytic cycle of a sodium-pumping pyrophosphatase.,Kellosalo J, Kajander T, Kogan K, Pokharel K, Goldman A Science. 2012 Jul 27;337(6093):473-6. PMID:22837527[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Perez-Castineira JR, Lopez-Marques RL, Losada M, Serrano A. A thermostable K(+)-stimulated vacuolar-type pyrophosphatase from the hyperthermophilic bacterium Thermotoga maritima. FEBS Lett. 2001 May 4;496(1):6-11. PMID:11343697
- ↑ Malinen AM, Belogurov GA, Baykov AA, Lahti R. Na+-pyrophosphatase: a novel primary sodium pump. Biochemistry. 2007 Jul 31;46(30):8872-8. Epub 2007 Jul 3. PMID:17605473 doi:http://dx.doi.org/10.1021/bi700564b
- ↑ Kellosalo J, Kajander T, Kogan K, Pokharel K, Goldman A. The structure and catalytic cycle of a sodium-pumping pyrophosphatase. Science. 2012 Jul 27;337(6093):473-6. PMID:22837527 doi:10.1126/science.1222505
- ↑ Kellosalo J, Kajander T, Kogan K, Pokharel K, Goldman A. The structure and catalytic cycle of a sodium-pumping pyrophosphatase. Science. 2012 Jul 27;337(6093):473-6. PMID:22837527 doi:10.1126/science.1222505
