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Product conformation driven splicing of unprotected peptides by reverse proteolysis: Influence of intrinsic and extrinsic factors

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Title Product conformation driven splicing of unprotected peptides by reverse proteolysis: Influence of intrinsic and extrinsic factors
 
Creator Srinivasulu, Sonati
Acharyal, A Seetharama
 
Description 240-252
The structural motif of ‘product conformation driven
V8 protease catalyzed ligation reaction’ can be represented by FRI-EALER-

FRII. The relative roles of the flanking
regions (FRI and FRII) and of splicedon, the central
penta-peptide, on the thermodynamic stability of the ‘conformational trap’ of
the product has been now evaluated as a function of co-solvent concentration.
The studies have established that the thermodynamic stability of the
conformational trap of α17-40 des23-26 with four different
splicedons (EALER. EALEV, EYGER, or EGAER) that differ in the intrinsic α-helical
potential of their amino acid residues and/or ability to generate i, i+4 side
chain interaction is a direct correlate of the n-propanol included α helical conformation of the product. On the
other hand, when the product is defined by only splicedon EALER, and the flanking
regions are disitinct; no correlation could be drawn between the stability of
the trap and solvent induced α- helical conformation, even though these
generally give an equilibrium yield of 45% in 30% n -propanol and is not influenced by an increased propanol
concentration. However, when the splicedon EALER with given FRI and
FRII region develops a

‘conformational trap’ of a lower stability in 30%
propanol as seen with  β18-25(A22)
-EAL ER-β31-39, the stability
increases in

60%  n -propanol, without significant
increase in the α- helical conformation. Though, primary structure of RNAse l-20,
could

be presented as RNAse1-5-AKFER- RNAsel1-20,
and α-helical conformation is induced to this peptide both in 30 and 60%

propanol, splicedon AKFER by itself does not develop
the ‘conformational trap’, of RNAse1-20. The splicedon AKFER of

RNAse1-20 fails to develop the ‘conformational
trap’, due to an intrinsic inhibitory potential of its FRII  region. RNAse11-20;

replacing RNAse11-20 with α32-40
enables the splicedon AFKER to generate the ‘conformational trap’ . The studies
presented

here have demonstrated the primary role of flanking
regions in establishing the amount of the solvent induced α-helical

conformation and that of the splicedon in dictating
the thermodynamic stability of its ‘conformational trap’ of the products, nonetheless
one influences the other to some degree. We suggest that the stability of the ‘conformational
trap’ of the product

reflects the ability of the splicedon to ‘recruit’ the
product conformation to protect the spliced peptide bond, i.e. to reduce

the helix-coil transition of the spliced region which
in turn imparts a degree of resistance to the spliced peptide bond.
 
Date 2012-12-22T19:56:19Z
2012-12-22T19:56:19Z
2002-08
 
Type Article
 
Identifier 0975-0959 (Online); 0301-1208 (Print)
http://hdl.handle.net/123456789/15267
 
Language en_US
 
Rights CC Attribution-Noncommercial-No Derivative Works 2.5 India
 
Publisher NISCAIR, CSIR
 
Source IJBB Vol.39(4) [August 2002]