Role of Charged Amino Acids in the Origin of UV-Visible Electronic absorption in proteins
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Proteins are the most abundant intracellular macromolecules which perform a diverse range of functions within the living cell. They are known to absorb in the UV region of the electromagnetic spectrum owing to the presence of aromatic amino acids (Trp, Tyr and Phe) in them. This absorption has been well characterized using UV-Visible spectroscopy. However, LLys. HCl (Lysine monohydrochloride), a non-aromatic amino acid was reported to display a unique absorption at 270 nm and luminescence feature at high concentrations (~0.5 M) in aqueous medium. These features could not be accounted for by any chromophore present in the Lys molecule and a possible role of the -NH2 moiety in Lys was anticipated. Similar observations arising from interactions between two or more lysine residues present in close spatial vicinity in lysine rich proteins like Human Serum Albumin have also been reported. However the origin of these novel spectra in the absence of any aromatic moiety has remained unanswered till date.
supervisor: R. Swaminathan
BIOSCIENCES AND BIOENGINEERING