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Article: Identification of a surface charged residue in the S3-S4 linker of the pacemaker (HCN) channel that influences activation gating

TitleIdentification of a surface charged residue in the S3-S4 linker of the pacemaker (HCN) channel that influences activation gating
Authors
KeywordsChemicals And Cas Registry Numbers
Issue Date2003
PublisherAmerican Society for Biochemistry and Molecular Biology, Inc. The Journal's web site is located at http://www.jbc.org/
Citation
Journal Of Biological Chemistry, 2003, v. 278 n. 16, p. 13647-13654 How to Cite?
AbstractIf, encoded by the hyperpolarization-activated cyclic nucleotide-modulated (HCN) channel family, is a key player in cardiac and neuronal pacing. Although HCN channels structurally resemble voltage-gated K+ (Kv) channels, their structure-function correlation is much less clear. Here we probed the functional importance of the HCN1 S3-S4 linker by multiple substitutions of its residues. Neutralizing Glu235, an acidic S3-S4 linker residue conserved in all hyperpolarization-activated channels, by Ala substitution produced a depolarizing activation shift (V1/2 = -65.0 ± 0.7 versus -70.6 ± 0.7 mV for wild-type HCN1); the charge-reversed mutation E235R shifted activation even more positively (-56.2 ± 0.5 mV). Increasing external Mg2+ mimicked the progressive rightward shifts of E235A and E235R by gradually shifting activation (V1/2 = 1 < 3 < 10 < 30 mM); ΔV1/2, induced by 30 mM Mg2+ was significantly attenuated for E235A (+7.9 ± 1.2 versus +11.3 ± 0.9 mV for wild-type HCN1) and E235R (+3.3 ± 1.4 mV) channels, as if surface charges were already shielded. Consistent with an electrostatic role, the energetic changes associated with ΔV1/2 resulting from various Glu235 substitutions (i.e. Asp, Ala, Pro, His, Lys, and Arg) displayed a strong correlation with their charges (ΔΔG = -2.1 ± 0.3 kcal/mol/charge; r = 0.94). In contrast, D233E, D233A, D233G, and D233R did not alter activation gating. D233C (in C318S background) was also not externally accessible when probed with methanethiosulfonate ethylammonium (MTSEA). We conclude that the S3-S4 linker residue Glu235 influences activation gating, probably by acting as a surface charge.
Persistent Identifierhttp://hdl.handle.net/10722/91425
ISSN
2015 Impact Factor: 4.258
2015 SCImago Journal Rankings: 3.151
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorHenrikson, CAen_HK
dc.contributor.authorXue, Ten_HK
dc.contributor.authorDong, Pen_HK
dc.contributor.authorSang, Den_HK
dc.contributor.authorMarban, Een_HK
dc.contributor.authorLi, RAen_HK
dc.date.accessioned2010-09-17T10:19:11Z-
dc.date.available2010-09-17T10:19:11Z-
dc.date.issued2003en_HK
dc.identifier.citationJournal Of Biological Chemistry, 2003, v. 278 n. 16, p. 13647-13654en_HK
dc.identifier.issn0021-9258en_HK
dc.identifier.urihttp://hdl.handle.net/10722/91425-
dc.description.abstractIf, encoded by the hyperpolarization-activated cyclic nucleotide-modulated (HCN) channel family, is a key player in cardiac and neuronal pacing. Although HCN channels structurally resemble voltage-gated K+ (Kv) channels, their structure-function correlation is much less clear. Here we probed the functional importance of the HCN1 S3-S4 linker by multiple substitutions of its residues. Neutralizing Glu235, an acidic S3-S4 linker residue conserved in all hyperpolarization-activated channels, by Ala substitution produced a depolarizing activation shift (V1/2 = -65.0 ± 0.7 versus -70.6 ± 0.7 mV for wild-type HCN1); the charge-reversed mutation E235R shifted activation even more positively (-56.2 ± 0.5 mV). Increasing external Mg2+ mimicked the progressive rightward shifts of E235A and E235R by gradually shifting activation (V1/2 = 1 < 3 < 10 < 30 mM); ΔV1/2, induced by 30 mM Mg2+ was significantly attenuated for E235A (+7.9 ± 1.2 versus +11.3 ± 0.9 mV for wild-type HCN1) and E235R (+3.3 ± 1.4 mV) channels, as if surface charges were already shielded. Consistent with an electrostatic role, the energetic changes associated with ΔV1/2 resulting from various Glu235 substitutions (i.e. Asp, Ala, Pro, His, Lys, and Arg) displayed a strong correlation with their charges (ΔΔG = -2.1 ± 0.3 kcal/mol/charge; r = 0.94). In contrast, D233E, D233A, D233G, and D233R did not alter activation gating. D233C (in C318S background) was also not externally accessible when probed with methanethiosulfonate ethylammonium (MTSEA). We conclude that the S3-S4 linker residue Glu235 influences activation gating, probably by acting as a surface charge.en_HK
dc.languageengen_HK
dc.publisherAmerican Society for Biochemistry and Molecular Biology, Inc. The Journal's web site is located at http://www.jbc.org/en_HK
dc.relation.ispartofJournal of Biological Chemistryen_HK
dc.subjectChemicals And Cas Registry Numbersen_HK
dc.subject.meshAlanine - chemistryen_HK
dc.subject.meshAmino Acid Motifsen_HK
dc.subject.meshAmino Acid Sequenceen_HK
dc.subject.meshAnimalsen_HK
dc.subject.meshCyclic Nucleotide-Gated Cation Channelsen_HK
dc.subject.meshElectrophysiologyen_HK
dc.subject.meshGlutamic Acid - chemistryen_HK
dc.subject.meshIon Channels - chemistry - metabolismen_HK
dc.subject.meshKineticsen_HK
dc.subject.meshMagnesium - pharmacologyen_HK
dc.subject.meshMembrane Potentialsen_HK
dc.subject.meshMiceen_HK
dc.subject.meshMolecular Sequence Dataen_HK
dc.subject.meshMutationen_HK
dc.subject.meshNerve Tissue Proteinsen_HK
dc.subject.meshOocytes - metabolismen_HK
dc.subject.meshPotassium - metabolismen_HK
dc.subject.meshPotassium Channelsen_HK
dc.subject.meshProtein Structure, Tertiaryen_HK
dc.subject.meshSequence Homology, Amino Aciden_HK
dc.subject.meshThermodynamicsen_HK
dc.subject.meshXenopusen_HK
dc.titleIdentification of a surface charged residue in the S3-S4 linker of the pacemaker (HCN) channel that influences activation gatingen_HK
dc.typeArticleen_HK
dc.identifier.emailLi, RA:ronaldli@hkucc.hku.hken_HK
dc.identifier.authorityLi, RA=rp01352en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1074/jbc.M211025200en_HK
dc.identifier.pmid12582169-
dc.identifier.scopuseid_2-s2.0-0037561997en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0037561997&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume278en_HK
dc.identifier.issue16en_HK
dc.identifier.spage13647en_HK
dc.identifier.epage13654en_HK
dc.identifier.isiWOS:000182405000013-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridHenrikson, CA=7004279066en_HK
dc.identifier.scopusauthoridXue, T=7005064190en_HK
dc.identifier.scopusauthoridDong, P=7102262581en_HK
dc.identifier.scopusauthoridSang, D=7004187916en_HK
dc.identifier.scopusauthoridMarban, E=8075977300en_HK
dc.identifier.scopusauthoridLi, RA=7404724466en_HK
dc.identifier.citeulike9076652-

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