TY - JOUR
T1 - Functional characterization of a prokaryotic Kir channel
AU - Enkvetchakul, Decha
AU - Bhattacharyya, Jaya
AU - Jeliazkova, Iana
AU - Groesbeck, Darcy K.
AU - Cukras, Catherine A.
AU - Nichols, Colin G.
PY - 2004/11/5
Y1 - 2004/11/5
N2 - The Kir gene family encodes inward rectifying K+ (Kir) channels that are widespread and critical regulators of excitability in eukaryotic cells. A related gene family (KirBac) has recently been identified in prokaryotes. While a crystal structure of one member, KirBac1.1, has been solved, there has been no functional characterization of any KirBac gene products. Here we present functional characterization of KirBac1.1 reconstituted in liposomes. Utilizing a 86Rb+ uptake assay, we demonstrate that KirBac1.1 generates a K+-selective permeation path that is inhibited by extraliposomal Ba2+ and Ca2+ ions. In contrast to KcsA (an acid-activated bacterial potassium channel), KirBac1.1 is inhibited by extraliposomal acid (pKa ∼ 6). This characterization of KirBac1.1 activity now paves the way for further correlation of structure and function in this model Kir channel.
AB - The Kir gene family encodes inward rectifying K+ (Kir) channels that are widespread and critical regulators of excitability in eukaryotic cells. A related gene family (KirBac) has recently been identified in prokaryotes. While a crystal structure of one member, KirBac1.1, has been solved, there has been no functional characterization of any KirBac gene products. Here we present functional characterization of KirBac1.1 reconstituted in liposomes. Utilizing a 86Rb+ uptake assay, we demonstrate that KirBac1.1 generates a K+-selective permeation path that is inhibited by extraliposomal Ba2+ and Ca2+ ions. In contrast to KcsA (an acid-activated bacterial potassium channel), KirBac1.1 is inhibited by extraliposomal acid (pKa ∼ 6). This characterization of KirBac1.1 activity now paves the way for further correlation of structure and function in this model Kir channel.
UR - http://www.scopus.com/inward/record.url?scp=8744224521&partnerID=8YFLogxK
U2 - 10.1074/jbc.C400417200
DO - 10.1074/jbc.C400417200
M3 - Article
C2 - 15448150
AN - SCOPUS:8744224521
SN - 0021-9258
VL - 279
SP - 47076
EP - 47080
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 45
ER -