NDLI: Effect of cysteine substitutions on the topology of the S4 segment of the Shaker potassium channel: implications for molecular models of gating

Content Provider	PubMed Central
Author	Wang, M-h Yusaf, S. P. Elliott, D. J. S. Wray, D. Sivaprasadarao, A.
Copyright Year	1999
Abstract	The gating properties of voltage-gated potassium channels are largely determined by the amino acid sequence of their S4 segments. To investigate the nature of S4 movement during gating, we introduced single cysteines into the S4 segment of the Shaker potassium channel and expressed the mutants in Xenopus oocytes. We then measured the conductance-voltage (g-V) relationships and the rate and the voltage dependence of movement of the engineered cysteines, using p-chloromercuribenzene sulphonate (pCMBS) as a probe. Mutation of charged residues at positions 362, 365 and 368, but not the uncharged residues (positions 360, 361, 363, 364 and 366), to cysteines shifted the g-V relationships to more positive potentials. Mutant channels in which cysteines replaced the charged residues at positions 362 and 365 (R362C and R365C) reacted faster with pCMBS than those in which cysteines were introduced in place of uncharged residues at positions 360 and 361 (I360C and L361C). Furthermore, the R365C mutant channel reacted with pCMBS even at hyperpolarised (-120 mV) potentials. Currents expressed by the doubly mutated R365S/V367C and R368S/V367C channels, but not the singly mutated V367C channel, were inhibited by pCMBS. Moreover, the R368C mutant channel was also affected by pCMBS. Voltage dependence of block by pCMBS (2 min exposure) was steeper for L366C than for L361C and V363C mutant channels (effective charge 2.19, 1.41 and 1.45, respectively). The voltage dependence of the pCMBS effect was also shifted to more depolarising potentials the deeper in the membrane the position of the residue mutated to cysteine (voltages for half-maximal effect -107, -94 and -73 mV for positions 361, 363 and 366, respectively). Our data show firstly that charge-neutralising mutations in S4 alter the topology of this region such that the membrane-spanning portion of S4 is reduced. Secondly, our data for the other mutant channels suggest that S4 might move in at least two sequential steps, and can move up to its maximal limit even at the resting potential of the cell.
Related Links	http://dx.doi.org/10.1111/j.1469-7793.1999.00315.x
Ending Page	326
Page Count	12
Starting Page	315
File Format	PDF
ISSN	00223751
e-ISSN	14697793
Journal	The Journal of Physiology
Issue Number	Pt 2
Volume Number	521
Language	English
Publisher	Blackwell Science Inc
Publisher Date	1999-12-01
Access Restriction	Open
Rights Holder	Blackwell Science Inc
Subject Keyword	Physiology Research in Higher Education
Content Type	Text
Resource Type	Article
Subject	Physiology Sports Science

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Amino terminal-dependent gating of the potassium channel rat eag is compensated by a mutation in the S4 segment.

Shaker potassium channel gating. III: Evaluation of kinetic models for activation

Three-dimensional structure of the S4-S5 segment of the Shaker potassium channel.

Voltage-insensitive Gating after Charge-neutralizing Mutations in the S4 Segment of Shaker Channels

Modulation of the Shaker K+Channel Gating Kinetics by the S3–S4 Linker

Role of the S3-S4 Linker in Shaker Potassium Channel Activation

Position and motions of the S4 helix during opening of the Shaker potassium channel

Histidine Scanning Mutagenesis of Basic Residues of the S4 Segment of the Shaker K+ Channel

Shaker potassium channel gating. II: Transitions in the activation pathway

Effect of cysteine substitutions on the topology of the S4 segment of the Shaker potassium channel: implications for molecular models of gating

Similar Documents

Amino terminal-dependent gating of the potassium channel rat eag is compensated by a mutation in the S4 segment.

Shaker potassium channel gating. III: Evaluation of kinetic models for activation

Three-dimensional structure of the S4-S5 segment of the Shaker potassium channel.

Voltage-insensitive Gating after Charge-neutralizing Mutations in the S4 Segment of Shaker Channels

Modulation of the Shaker K+Channel Gating Kinetics by the S3–S4 Linker

Role of the S3-S4 Linker in Shaker Potassium Channel Activation

Position and motions of the S4 helix during opening of the Shaker potassium channel

Histidine Scanning Mutagenesis of Basic Residues of the S4 Segment of the Shaker K+ Channel

Shaker potassium channel gating. II: Transitions in the activation pathway

Effect of cysteine substitutions on the topology of the S4 segment of the Shaker potassium channel: implications for molecular models of gating