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Re: [ccp4bb]: C-H...O type interaction



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The Calpha hydrogen bonds have been frequently observed during the last
years. The role of these interactions seems to be underestimated. There
are some interessting papers about the occurrence of Calpha hydrogen
bonds:

-> Jiang L, Lai L. CH...O hydrogen bonds at protein-protein
interfaces.(2002) J Biol Chem, 277(40).37732-40.
-> Senes A et al. The Calpha ---H...O hydrogen bond: a determinant of
stability and specificity in                    transmembrane helix
interactions. (2001) PNAS, 98(16):9056-6.
-> Derewenda ZS, Lee L, Derewenda U.The occurrence of C-H...O hydrogen
bonds in proteins. (1995) J Mol Biol,          252(2):248-62

The last paper gives you a nice discription of all parameters like
angles and distances defining a Calpha hydrogen bond.


Bernhard Loll


Narayanan Ramasubbu wrote:
> 
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> ***          CCP4 home page http://www.ccp4.ac.uk         ***
> 
> Hello all:
> This is not a CCP4 question but I would like to find out opinion about a
> peculiar interaction that I notice in my protein.
> There is a C-H...O type interaction (H bond perhaps?) from an indole ring
> to a catalytic Asp (Trp to Asp). Mutation of Trp to either Tyr or Leu or
> Ala reduces activity. Other than this interaction, Trp is part of a
> classic hydrophobic interaction with a His and Trp.
> 1) Has anybody come across this type of situation in other enzymes?
> 2) How does the negative density of a Asp carboxyl group get affected
>  by an aromatic residue?
> 3) Can the pKa of the carboxyl group be affected in the wild type or
> in the mutants?
> The resolution is 2.0 A and the distance is 3.2 A.
> thanks in advance
> subbu
> 
> subbu@xray.UMDNJ.EDU

-- 



Bernhard Loll
FU-Berlin
Institut fuer Kristallographie
AG Saenger
Takustr. 6
14195 Berlin
TEL +49-(0)3083856758
FAX +49-(0)3083856702
loll@chemie.fu-berlin.de