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Date: November 28, 2012 8:18:37 AM EST To: "William G. Scott" <wgsc...@ucsc.edu<mailto:wgsc...@ucsc.edu>> Subject: Re: [ccp4bb] Mg++ interactions Bill, I cannot answer your question, except to comment that in many, if not all Class I aminoacyl-tRNA synthetases, Mg++ is indirectly linked to three lysine residues via phosphate oxygen atoms, two of which are shared with Mg++. I've assumed that negative charge on the oxygen atoms was responsible for this coupling. Despite the fact that this unusual coordination has no direct impact on catalysis ((Weinreb, et al., (2009) Structure 17:952), it does provide the catalytically relevant link between ATP utilization and domain movement (Weinreb, Li, & Carter (2012) Structure 20:128). I would be surprised to see a direct interaction between a primary amine and Mg++. Charlie On Nov 28, 2012, at 12:46 AM, William G. Scott wrote: Hi folks: Are Mg++ ions ever observed to chelate primary amines? Are there any examples in crystal structures? Thanks. -- Bill William G. Scott Professor Department of Chemistry and Biochemistry and The Center for the Molecular Biology of RNA 228 Sinsheimer Laboratories University of California at Santa Cruz Santa Cruz, California 95064 USA
