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Compensatory secondary structure alterations in protein glycation
Ranjita GhoshMoulick1, Jaydeep Bhattacharya, Shibsekhar Roy
1Department of Biochemistry, Calcutta University, 35 Ballygunge Circular Road, Calcutta 700019, India.
Biochimica Et Biophysica Acta
|January 20, 2007
Summary
Fructose glycation significantly alters hemoglobin structure more than glucose, affecting protein folding and fluorescence. These changes indicate distinct glycation stages and depend on accessible sites and protein assembly.
Area of Science:
- Biochemistry
- Protein Chemistry
- Spectroscopy
Background:
- Glycation is a post-translational modification affecting protein structure and function.
- Hemoglobin glycation, particularly with fructose, leads to structural changes.
- Understanding these alterations is crucial for studying protein stability and disease mechanisms.
Purpose of the Study:
- To investigate the structural and fluorescence changes in hemoglobin upon glycation by glucose and fructose.
- To elucidate the stages and mechanisms of hemoglobin glycation.
- To correlate structural changes with accessible glycation sites and protein subunit assembly.
Main Methods:
- Spectroscopic analysis (fluorescence spectroscopy) to monitor structural changes.
- Measurement of Stokes diameter to assess overall size changes.
- Analysis of secondary structure (alpha helix, beta sheet, random coil) changes.
Main Results:
- Fructose glycation caused more pronounced structural alterations than glucose glycation.
- Hemoglobin's Stokes diameter increased, accompanied by cross-linking and heme loss.
- Fluorescence studies revealed energy transfer between tryptophan and advanced glycosylation end products (AGEs) in later glycation stages.
- A shift from alpha helix to beta sheet and random coil structures was observed, dependent on solvent-accessible sites.
Conclusions:
- Hemoglobin glycation involves distinct stages, with fructose-induced changes being more significant.
- Structural modifications include increased size, cross-linking, heme loss, and altered secondary structures.
- The extent of glycation-induced structural changes is influenced by accessible modification sites and hemoglobin's subunit assembly.
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