KChannelDB: Extraction of mutation data from the literature

2005, KChannelDB.

This data was extracted from Medline abstracts and full texts (when available) in an automated manner.

The table below describes the selected point mutation and provides links to other documents. The sentence(s) where the point mutation E283Q was found are listed after the table.

The mutated residues are also indicated in the family sequence alignments and hyperlinked to the corresponding mutation pages.

Point mutation E283Q in KCAB2_HUMAN

Point mutation:	E283Q
Domain:	Not determined
General numbering (KChannelDB):	-
Protein:	KCAB2_HUMAN (KCNAB2,KCNA2B, KCNK)	Swiss-Prot Cross-reference table Family page
Protein isoforms	2
Other point mutations / same protein / same position	Point mutations at position 283 in KCAB2_HUMAN
Other point mutations / same protein	List of mutations in KCAB2_HUMAN
Family alignments	Potassium channel beta subunits KvBeta
Other point mutations / same position	Position 335 in Potassium channel beta subunits KvBeta family
Reference:	Histidine scanning mutagenesis of basic residues of the S4 segment of the shaker k+ channel. Starace DM, Bezanilla F J Gen Physiol 2001 May;117(5):469-90.	Medline
Other point mutations / same article	List
Text source	HTML full text
Validation status	Not yet checked

Relevant sentences:

E283Q

E283Q / R371H Channel There is evidence for the existence of charged networks between acidic residues in the S2 and S3 transmembrane segments and some of the basic residues in S4 (Tiwari-Woodruff et al. 1997 (image) , Tiwari-Woodruff et al. 2000 (image) )
Addition of the neutralizing mutation , E283Q , to the R371H channel slowed the gating current kinetics by ~10-fold (Fig 12 A)
Gating currents of the E283Q / R371H channel
(A) Using the cut-open oocyte voltage clamp , E283Q / R371H channel gating currents were measured in symmetric NMDG-MS solutions with internal pH 9.2 , and either pH o 9.2 (top currents) or pH o 5 (bottom currents)
(Experiment D11037a) Since E283Q / R371H channel charge displacement is asymmetric in a pH gradient , a proton current should accompany each voltage sensor stroke
The properties of the steady-state ON-gating currents of the E283Q / R371H channel resemble those of the R371H channel in many respects except one: the sizes of the proton currents are dramatically reduced
The steady-state ON-gating currents from the E283Q / R371H channel are barely above the background , making it difficult to attribute them to something as specific as proton transport and / or conduction by the histidine at position 371
The slow kinetics of the E283Q / R371H channel gating currents indicate slow voltage sensor transitions
The reduction of E283Q / R371H channel proton current amplitudes is consistent with both transport and pore formation by 371H
Although E283Q neutralization makes no progress in determining the composition of R371H proton currents , it does suggest some interesting ways of designing effective proton pores
However , addition of the neutralizing mutation (E283Q) to the R368H channel did not alter the gating or proton transport properties of the channel at all (data not shown)

F.Horn (kchanneldbcmbi.ru.nl), 17-Aug-2005