4KPP

Crystal Structure of H+/Ca2+ Exchanger CAX

Summary for 4KPP

• Entry DOI: 10.2210/pdb4kpp/pdb
• Related PRD ID: PRD_900001
• Descriptor: Putative uncharacterized protein, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, CALCIUM ION, ... (6 entities in total)
• Functional Keywords: membrane protein, transporter
• Biological source: Archaeoglobus fulgidus
• Total number of polymer chains: 2
• Total formula weight: 92222.52

Authors

Nishizawa, T.,Ishitani, R.,Nureki, O. (deposition date: 2013-05-14, release date: 2013-06-26, Last modification date: 2024-05-29)

Primary citation

Nishizawa, T.,Kita, S.,Maturana, A.D.,Furuya, N.,Hirata, K.,Kasuya, G.,Ogasawara, S.,Dohmae, N.,Iwamoto, T.,Ishitani, R.,Nureki, O.
Structural basis for the counter-transport mechanism of a H+/Ca2+ exchanger.
Science, 341:168-172, 2013

PubMed Abstract: 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 Å 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.

PubMed: 23704374
DOI: 10.1126/science.1239002

Experimental method

X-RAY DIFFRACTION (2.3 Å)