Zn binding

Fig. 19.10 Flow chart for the NMR identification of novel scaffolds for Zn binding.

Zn-binding domain, present in CBP/p300 and Dystrophin. In Dystrophin, domain is implicated in Calmodulin binding. Mis-sense mutation of conserved cysteine correlates with Duchenne muscular dystrophy. 

Description (CD ID) Consensus Function Examples in RING proteins (Cenebank Accession) Zn-binding domain R rences... 

Fig. 4. The eNOS Zn binding site. The Zn is tetrahedrally coordinated by two pairs of symmetry-related Cys residues. Because the Zn is located exactly along the dimer axis of symmetry, the Zn is equidistant from each heme and pterin. Three residues apart from one Cys hgand in each subunit is Serl04, which directly H-bonds with the pterin. The Zn helps to stabihze these interactions in the pterin site the pterin, in turn, helps to shape the L-Arg binding site, since both L-Arg and the pterin H-bond with the same heme propionate. Hence, there is long-range structural communication among the Zn, pterin, and substrate.

Johnson, C. A. Kersten, M. 1999. A possible mechanism of Zn binding to Ca silicate hydrates. Environmental Science and Technology, 33, 2296-2298. 

Fig. 1.3. Complexation of Ztf in the Zn-binding motif a) classical Cys2His2 finger b) Zn Cys4 binding motif c) (Zn )2 Cys binding motif...

Fig. 1.4. Structures of Zn binding motifs, a) TFIIA-like Zn Cys2His2 finger b) the binuclear (Zn )2 Cys motif of the GAL4 transcription activator c) The DNA-binding domain of the gluccocorticoid receptor. The Zn ions are drawn as spheres. MOL-SCRIPT drawing (Kraulis, 1991).

Fig. 1.6. The Zn binding motif of the glncocorticoid receptor in complex with DNA. Shown is the complex of the dimeric DNA-binding domain of the glncocorticoid receptor with the cognate DNA element (Luisi et al., 1991). The Zn ions are shown as spheres. The two Zn ions are clearly non-eqnivalent. While one of the Zn ions aids in the fixation of the recognition helix in the major groove, the other correctly positions a strnctnral element for the dimerization of the monomers. MOLSCRIPT drawing (Kranhs, 1991).

The metal ion is lost reversibly from the Zn-binding site of BESOD below pH 4. With the (Cu",Cu")-derivative an EPR spectrum at g — 2 appeared reversibly, suggesting the loss of Cu from the Zn-binding site . With the Zn-free (Cu ,—)-BESOD a reversible migration of Cu from one subunit to the Zn site of another, was observed to occur with a pK of 8.2 by the decrease of the EPR signal at 30 °C . 

Complexation of Zn11 with ATP results in a significant shift of the H-8 resonance which is taken as evidence of Zn binding to the N-7 atom. The effect of coordination on the C(8)-H bond also explains the formation of a metal-C(8) bond with the MeHg+ ion.120 Multinuclear NMR has been used to identify a number of Al111 complexes of ATP in solution, and the results related to the involvement of Al in dialysis dementia disease.121... 

Within the normal conditions of biological systems, thiolates are disfavored compared to thiols. Thiols are even weaker nucleophiles than thiolates. For methi-nonine synthase this problem is overcome by having a Zn binding site for homocysteine [171], The relative reactivity should be RS > RSM > RSH. 

Bestor TH. Activation of mammalian DNA methyltransferase by cleavage of a Zn binding regulatory domain. EMBO J 1992 11 2611-2617. 

Chuang LS, Ng HH, Chia JN, Li BF. Characterisation of independent DNA and multiple Zn-binding domains at the N terminus of human DNA-(cyto-sine-5) methyltransferase modulating the property of a DNA-binding domain by contiguous Zn-binding motifs. J Mol Biol 1996 257 935-948. 

Fig. 14 Zn binding to the homochiral Zn alkoxide, monitored by the 13-C shifts of the two alkyne protons and demonstrating the higher degree of association in toluene compared to thf...

Further analysis was done on the multiple sequence alignment of the H. pylori protein with members of the AstE AspA family. Amino acid residues corresponding to bovine carboxypep-tidase A responsible for Zn binding (Glu-72, His-69), carboxy-late binding (Arg-145), and catalytic residues (Glu-270) (58) are conserved in the H. pylori sequence. However, Zn-binding residues corresponding to His-69 are substituted by Gin, suggesting the possibility that this H. pylori protein is related to this enzymatic family (Fig. 8). 

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