Structural highlights
Function
[KCSA_STRLI] Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+).[1]
Publication Abstract from PubMed
Modal-gating shifts represent an effective regulatory mechanism by which ion channels control the extent and time course of ionic fluxes. Under steady-state conditions, the K(+) channel KcsA shows three distinct gating modes, high-P(o), low-P(o) and a high-frequency flicker mode, each with about an order of magnitude difference in their mean open times. Here we show that in the absence of C-type inactivation, mutations at the pore-helix position Glu71 unmask a series of kinetically distinct modes of gating in a side chain-specific way. These gating modes mirror those seen in wild-type channels and suggest that specific interactions in the side chain network surrounding the selectivity filter, in concert with ion occupancy, alter the relative stability of pre-existing conformational states of the pore. The present results highlight the key role of the selectivity filter in regulating modal gating behavior in K(+) channels.
On the structural basis of modal gating behavior in K(+) channels.,Chakrapani S, Cordero-Morales JF, Jogini V, Pan AC, Cortes DM, Roux B, Perozo E Nat Struct Mol Biol. 2011 Jan;18(1):67-74. Epub 2010 Dec 26. PMID:21186363[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Schrempf H, Schmidt O, Kummerlen R, Hinnah S, Muller D, Betzler M, Steinkamp T, Wagner R. A prokaryotic potassium ion channel with two predicted transmembrane segments from Streptomyces lividans. EMBO J. 1995 Nov 1;14(21):5170-8. PMID:7489706
- ↑ Chakrapani S, Cordero-Morales JF, Jogini V, Pan AC, Cortes DM, Roux B, Perozo E. On the structural basis of modal gating behavior in K(+) channels. Nat Struct Mol Biol. 2011 Jan;18(1):67-74. Epub 2010 Dec 26. PMID:21186363 doi:10.1038/nsmb.1968
