Spectroscopic and lipid binding studies on the amino and carboxyl terminal fragments of Locusta migratoria apolipophorin III

Biochemistry
V NarayanaswamiR O Ryan

Abstract

The structural basis for the lipid binding capability of Locusta migratoria apolipophorin III (apoLp-III) was assessed by characterizing the amino and carboxyl terminal halves of the protein. The native molecule (approximately 20 kDa) was deglycosylated with endoglycosidase F (molecular mass of deglycosylated species approximately 18 kDa) and cleaved with endoproteinase Arg-C to yield two fragments with molecular masses of approximately 9 kDa each. The two fragments were purified by reversed-phase HPLC and identified by mass spectrometry, amino acid analysis and N-terminal sequencing as the amino terminal (N9) and carboxyl terminal (C9) halves. Due to the apparent discrepancy of the protease digestion pattern obtained compared to that expected from the deduced amino sequence of apoLp-III cDNA, we carried out partial amino acid sequencing of the fragments and cDNA sequencing for the entire protein. Circular dichroism spectroscopy of the N9 and C9 peptides revealed that both exist in buffer in a random coil state. However, addition of trifluoroethanol, a helix-inducing agent, resulted in the formation of an alpha-helix, reflecting an innate propensity of the peptides to adopt a helical conformation. When cosonicated with dimyrist...Continue Reading

Citations

Oct 7, 2011·Applied Biochemistry and Biotechnology·Zulfiqar A Malik, Sumaira Amir
Nov 6, 2003·Insect Biochemistry and Molecular Biology·P M Weers, R O Ryan
Aug 26, 1998·Biochimica Et Biophysica Acta·P M WeersR O Ryan
Dec 22, 1999·Biochimica Et Biophysica Acta·V Narayanaswami, R O Ryan
May 20, 2009·Biochimica Et Biophysica Acta·Lesley J VasquezP M Weers
Oct 25, 1996·The Journal of Biological Chemistry·V NarayanaswamiR O Ryan

Related Concepts

Apolipophorin-II
Metazoa
Apolipoproteins
DNA Sequence
Carrier Proteins
Circular Dichroism, Vibrational
Romaleidae
Electron Microscopy
Peptide Fragments
Plasma Protein Binding Capacity

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