biophysics vs. biochem speculatin'....

George Munson george-munson at nwu.edu
Thu Nov 2 22:30:34 EST 1995


> Got a question that's been puzzling me.  My cat's fur is so soft that
> petting him is like touching a cashmere or angora sweater.  My question
> is this - is *softness* due to:  
> 
> a) the **physical** arrangement of the peptide bonds - do the bonds and
> the amino acids they're attached to form a smooth, rather than jagged
> or discrete, surface?
> 
> b) the tertiary or quarternary folding of the protein(s) in his fur -
> ie, are the proteins physically arranged in some special way so that
> they are experienced by us as being *soft*?
> 
> c) the sequencing of the amino acids themselves, or
> 
> d) some other phenomenom that I haven't thought of and probably can't
> even imagine right now?

Hmm.  Okay this is my best guess and I chose "b."  I doubt tactile
perception is sensitive enough to distinguish peptide bonds or aa sequence
per se.  What you perceive is the much larger scale of the hair which is
of course ultimately a result of c, a, and b.  My guess is softness is
related to rigidity or the lack thereof.  Rigidity of the overall hair
would likely arise from intermolecular disulfide cross linkages which
would be tertiary/quartenary in nature.
-- 
George Munson
BMBCB, Northwestern University
Evanston, IL   USA   
george-munson at nwu.edu



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