NpgRJ_Nsmb_1311 1089..1095
نویسندگان
چکیده
K+ channels conduct and regulate K+ flux across the cell membrane. Several crystal structures and biophysical studies of tetrameric ion channels have revealed many of the structural details of ion selectivity and gating. A narrow pore lined with four arrays of carbonyl groups is responsible for ion selectivity, whereas a conformational change of the four inner transmembrane helices (TM2) is involved in gating. We used NMR to examine full-length KcsA, a prototypical K+ channel, in its open, closed and intermediate states. These studies reveal that at least two conformational states exist both in the selectivity filter and near the C-terminal ends of the TM2 helices. In the ion-conducting open state, we observed rapid structural exchange between two conformations of the filter, presumably of low and high K+ affinity, respectively. Such measurements of millisecond-timescale dynamics reveal the basis for simultaneous ion selection and gating.
منابع مشابه
Sports Med 2007; 37 (12): 1089-1099
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1089 1. Warm-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1090 1.1 Definition of Warm-Up . . . . . . . . . . . . . . ...
متن کاملPotentiation of radiation sensitivity in breast tumor cells by the vitamin D3 analogue, EB 1089, through promotion of autophagy and interference with proliferative recovery.
1,25-Dihydroxyvitamin D(3) and vitamin D(3) analogues, such as EB 1089, potentiate the response to ionizing radiation in breast tumor cells. The current studies address the basis for this interaction by evaluating DNA damage and repair, the effect of interference with reactive oxygen generation, the involvement of p53 and caspase-3, signaling through c-myc, as well as the induction of senescenc...
متن کاملThe combination of a potent vitamin D3 analog, EB 1089, with ionizing radiation reduces tumor growth and induces apoptosis of MCF-7 breast tumor xenografts in nude mice.
PURPOSE The purpose of this research was to evaluate theinfluence of the combination of the vitamin D(3) analogue EB 1089 with fractionated radiation on growth and apoptosis of MCF-7 tumor xenografts in athymic mice. EXPERIMENTAL DESIGN Four to six-week-old ovariectomized mice were injected s.c. with MCF-7 tumor cells suspended in Matrigel. When tumors reached a size of approximately 150-200 ...
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Treatment Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1089 Nonoperative Management . . . . . . . . . . . . . . . . . . . . . . . . . 1089 Primary Repair Versus Arthroscopic Debridement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1089 Microfracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1092 Au...
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