Publication Date:
2013-05-25
Description:
Ca(2+)/cation antiporters catalyze the exchange of Ca(2+) with various cations across biological membranes to regulate cytosolic calcium levels. The recently reported structure of a prokaryotic Na(+)/Ca(2+) exchanger (NCX_Mj) revealed its overall architecture in an outward-facing state. Here, we report the crystal structure of a H(+)/Ca(2+) exchanger from Archaeoglobus fulgidus (CAX_Af) in the two representatives of the inward-facing conformation at 2.3 A resolution. The structures suggested Ca(2+) or H(+) binds to the cation-binding site mutually exclusively. Structural comparison of CAX_Af with NCX_Mj revealed that the first and sixth transmembrane helices alternately create hydrophilic cavities on the intra- and extracellular sides. The structures and functional analyses provide insight into the mechanism of how the inward- to outward-facing state transition is triggered by the Ca(2+) and H(+) binding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nishizawa, Tomohiro -- Kita, Satomi -- Maturana, Andres D -- Furuya, Noritaka -- Hirata, Kunio -- Kasuya, Go -- Ogasawara, Satoshi -- Dohmae, Naoshi -- Iwamoto, Takahiro -- Ishitani, Ryuichiro -- Nureki, Osamu -- New York, N.Y. -- Science. 2013 Jul 12;341(6142):168-72. doi: 10.1126/science.1239002. Epub 2013 May 23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23704374" target="_blank"〉PubMed〈/a〉
Keywords:
Antiporters/*chemistry/genetics/metabolism
;
Archaeal Proteins/*chemistry/genetics/metabolism
;
Archaeoglobus fulgidus/*metabolism
;
Binding Sites
;
Calcium/chemistry/metabolism
;
Cation Transport Proteins/*chemistry/genetics/metabolism
;
Crystallography, X-Ray
;
Hydrogen/chemistry/metabolism
;
Protein Structure, Secondary
;
Protein Structure, Tertiary
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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