Partial Amino Acid Sequence of gamma-46 Gliadin

T. A. Egorov^1*, T. I. Odintsova², A. K. Musolyamov¹, S. F. Barbashov¹, V. N. Pustobaev¹, J. Andersen³, P. Roepstorff³, and Y. Popineau⁴

¹Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow, 117984 Russia; fax: (095) 135-1405; E-mail: egorov@imb.imb.ac.ru

²Vavilov Institute of General Genetics, Russian Academy of Sciences, ul. Gubkina 3, Moscow, 117809 Russia

³Department of Molecular Biology, Odense University, DK-5230 Odense M, Denmark

⁴Laboratory of Technology and Biochemistry of Proteins, INRA, 44026 Nantes Cedex, France

^* To whom correspondence should be addressed.

Received December 4, 1997; Revision received May 6, 1998

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We have determined the partial amino acid sequence (207 amino acids) of gamma-46 gliadin isolated from wheat cultivar Hardi. The molecular mass of the protein (M_r) estimated by electrospray mass spectrometry is 35191.3. The number of cysteine residues in gamma-46 gliadin was determined as a mass difference of the protein before and after reduction and alkylation with 4-vinylpyridine. It was shown that the protein has no free SH-groups, and all cysteine residues are involved in the formation of four disulfide bonds. The partial structure of gamma-46 gliadin was determined by N-terminal sequencing and sequencing of tryptic and chymotryptic peptides. The tryptic peptides were obtained by enzymatic hydrolysis of the protein, which was preliminarily reduced and immobilized at free SH-groups on thiopropyl-Sepharose 6B. The chymotryptic peptides were isolated by limited digestion of the native protein. The positions of cysteine residues, as well as surrounding amino acid sequences, are conserved in gamma-46 gliadin; this is typical of gliadins.

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KEY WORDS: storage proteins, prolamins, gliadins, cysteine residues, cysteine-containing peptides, mass spectrometry

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