TITLE

Studies on the Acid Induced Unfolding of Human Serum Albumin

AUTHOR(S)
Salahuddin, Parveen
PUB. DATE
March 2009
SOURCE
Protein & Peptide Letters;Mar2009, Vol. 16 Issue 3, p324
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The acid induced unfolding of HSA (Human Serum Albumin) was studied using UV-difference spectroscopy, fluorescence spectroscopy and far-UV CD spectroscopy. In UV-difference spectroscopy, the molar extinction coefficient decreased from N state to F state. Partially buried Tyr residues are transferred from a medium of high polarizability (native N state ) to a medium of low polarizability (F state). This is followed by loss of two electrostatic interactions Lys 205-Glu 465 and Arg218-Asp451 or one electrostatic interaction Lys205-Glu 465 / Arg218-Asp451 and one buried carboxyl group of acidic amino acid. Similarly, UV-difference spectroscopy showed a decrease in absorbance in F⇌E transition due to exposure of completely buried tyrosine residues from medium of high polarizability (F state) to a medium of low polarizability (E state). This is also followed by loss of one electrostatic interaction out of three electrostatic interactions namely, Asp187-Lys432, Asp187-Lys521 and Lys190-Glu425. The tryptophanyl fluorescence spectra showed that the N⇌F transition is accompanied by a decrease in fluorescence intensity. This implies that there is partial exposure of Trp214 to aqueous environment. Consequently, there is a loss of two electrostatic interactions Lys 205-Glu 465 and Arg218-Asp451 or one electrostatic interaction Lys205-Glu 465 / Arg218-Asp451 and one buried carboxyl group of acidic amino acid in N⇌F transition. The tryptophanyl fluorescence spectroscopy also showed that partially exposed Trp214 residue becomes nearly completely exposed in F⇌E transition. This is also followed by loss of two electrostatic interactions out of three Asp 187-Lys432,Asp187-Arg521 and Lys190-Glu425 in F⇌E transition. Taken together, these results showed that in N⇌F and F⇌E transitions a different number of electrostatic interaction is detected by different techniques. Secondly, in both N⇌F and F⇌E transitions, chromophoric groups are exposed first to aqueous environment and this is followed by loss of electrostatic interactions.
ACCESSION #
38025670

 

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics