Publication Date:
2012-07-28
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kellosalo, Juho -- Kajander, Tommi -- Kogan, Konstantin -- Pokharel, Kisun -- Goldman, Adrian -- New York, N.Y. -- Science. 2012 Jul 27;337(6093):473-6. doi: 10.1126/science.1222505.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural Biology and Biophysics Program, Institute of Biotechnology, Post Office Box 65, University of Helsinki, FIN-00014, Finland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22837527" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Bacterial Proteins/chemistry/genetics/metabolism
;
Biocatalysis
;
Calcium/chemistry
;
Catalytic Domain
;
Cell Membrane/enzymology
;
Crystallography, X-Ray
;
Diphosphates/*metabolism
;
Hydrolysis
;
Hydrophobic and Hydrophilic Interactions
;
Ion Channel Gating
;
Magnesium/chemistry
;
Models, Molecular
;
Molecular Sequence Data
;
Mutation
;
Protein Conformation
;
Protein Multimerization
;
Protein Structure, Secondary
;
Pyrophosphatases/*chemistry/genetics/*metabolism
;
Sodium/*metabolism
;
Sodium-Potassium-Exchanging ATPase/*chemistry/genetics/metabolism
;
Thermotoga maritima/*enzymology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
