Ca2+-ATPases are members of the P-type transporters and are usually regarded as post-stimulus recovery mechanisms, allowing calcium ions to be removed from the cytosol either via re-accumulation into sarcoplasmic/endoplasmic reticulum (the SERCA pumps) or extrusion outside the cell (the PMCA pumps). Here, Norimatsu and colleagues (1) have used X-ray solvent contrast modulation to assess density maps of four activation states of the SERCA1, focussing on the interaction between the ten transmembrane helices and their surrounding phospholipid environment. Their observations suggest an unexpected movement of the transporter core, which allows an exaggerated ‘waving’ of the cytoplasmic-extended calcium-binding domain during the cycle of calcium transport.
[1] Norimatsu et al. (2017). Protein-phospholipid interplay revealed with crystals of a calcium pump. Nature 545(7653):193-198. [PMID:28467821]
Comments by Steve Alexander (@mqzspa)
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