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Magnesium binding modes

Zinc will bind nitrogen and sulfur in a tetrahedral manner. This is also a fairly rigid structural arrangement, but, because it is so different from the binding mode of magnesium, can be used to exclude it from that site. [Pg.275]

Since then, a considerable amount of structural and mechanistic information has been collected and yeast enolase is probably the best understood sequential enzyme to date. It is a homodimer and requires two Mg + ions per active site for catalytic activity under physiological conditions, although magnesium can be replaced with a variety of divalent metal ions in vitro. During a catalytic turnover, the metal ions bind to the active site in a kinetically ordered, sequential manner with differential binding affinities. The mode of action of yeast enolase is illustrated in Figure 26 and is unusually well understood since several solid-state structures for each intermediate identified with kinetic methods have been determined. [Pg.349]

In binding experiments, the affinity of magnesium ADP to native membranes and to the isolated calcium dependent ATPase was found to be considerably lower than that of magnesium ATP173. On the other hand, from the inhibition of the calcium-dependent ATPase or the activation of calcium release and ATP synthesis apparent affinities for ADP are obtained that are very similar to those of ATP (Fig. 12). The affinity of ADP for the enzyme apparently depends on its functional state. The affinity of ADP for the membranes under conditions of calcium release depends markedly on the pH of the medium. When the medium pH is reduced from 7.0 to 6.0, the affinity drops by a factor of 10. At pH 7.0 the affinity of the membrane for ADP corresponds to the affinity for ATP to the high affinity binding sites in the forward running mode of the pump. In contrast to the complex dependence of the forward reaction on the concentration of ATP, the dependence of the reverse reaction on ADP seems to follow simple Michaelis-Menten kinetics. [Pg.38]

Figure 3 Coordination modes for magnesium ion binding to a variety of E. coli proteins (reproduced with... Figure 3 Coordination modes for magnesium ion binding to a variety of E. coli proteins (reproduced with...

See other pages where Magnesium binding modes is mentioned: [Pg.320]    [Pg.320]    [Pg.321]    [Pg.322]    [Pg.324]    [Pg.335]    [Pg.318]    [Pg.165]    [Pg.1111]    [Pg.196]    [Pg.345]    [Pg.322]    [Pg.34]    [Pg.202]    [Pg.33]    [Pg.318]    [Pg.328]    [Pg.332]    [Pg.378]    [Pg.475]    [Pg.202]    [Pg.56]    [Pg.310]    [Pg.627]    [Pg.77]    [Pg.240]    [Pg.257]    [Pg.176]    [Pg.1121]    [Pg.125]    [Pg.131]    [Pg.282]    [Pg.415]    [Pg.634]   
See also in sourсe #XX -- [ Pg.320 , Pg.321 , Pg.322 , Pg.323 , Pg.331 ]




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Binding modes

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