Re: [ccp4bb] Nucleophilic attack by the side-chain carboxyl group of Asp?

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: Re: Nucleophilic attack by the side-chain carboxyl group of Asp?
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2012-07-21

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Subject: Re: Nucleophilic attack by the side-chain carboxyl group of Asp?
From: "William G {- dot -} Scott" wgscott {- at -} UCSC {- dot -} EDU
Date: 2012-07-22

On Jul 21, 2012, at 11:52 AM, Justin Jones wrote:

> Unfortunately, their [sic] isn't a "general rule" for good versus bad nucleophiles.

Actually, there is: The theory of hard and soft acids and bases, developed by Ralph Pearson, generalizes to nucleophiles and electrophiles (Lewis bases and acids, respectively).

cf: http://en.wikipedia.org/wiki/HSAB_theory

Briefly, "hard" nucleophiles prefer "hard" electrophiles, and interact primarily via electrostatic attraction, and "soft" nucleophiles prefer "soft" electrophiles, and orbital interactions dominate.

So Mg++ prefers oxygen to sulphur, and Hg++ prefers sulphur to oxygen.

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

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Nucleophilic attack by the side-chain carboxyl group of Asp?
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2012-07-21

Next message:
Subject: off topic about coot crash!
From: Jai-Shin Liu d888223 {- at -} OZ {- dot -} NTHU {- dot -} EDU {- dot -} TW
Date: 2012-07-23