title: cDNA and protein sequence of a major pea seed albumin (PA 2 : Mr≈26 000).
abstract: Pea albumin 2 (PA2:Mr≈26000) is a major component of the albumin fraction derived from aqueous salt extracts of pea seed. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and chromatography on DEAE-Sephacel resolve PA2 into two closely related components (PA2a and PA2b). A cDNA clone coding for one of these components has been sequenced and the deduced amino acid sequence compared with partial, chemically-determined sequences for cyanogen bromide peptides from both PA2 components. Complete amino acid sequences were obtained for the C-terminal peptides. The PA2 molecule of 230 amino acids contains four imperfect repeat sequences each of approximately 57 amino acids in length.The combined sequence data, together with a comparison of PA2-related polypeptides produced in vitro and in vivo, indicate that PA2 is synthesized without a signal sequence and does not undergo significant post-translational modification. Although both forms of PA2 contain Asn-X-Thr consensus sequences, neither form is glycosylated. Accumulation of PA2 contributes approximately 11% of the sulfur-amino acids in pea seeds (cysteine plus methionine equals 2.6 residues percent). Suppression of levels of PA2 polypeptides and their mRNAs in developing seeds of sulfur-deficient plants is less marked than that for legumin, in spite of the lower content of sulfur-amino acids in legumin.
authors.affiliation: Division of Plant Industry, CSIRO, GPO Box 1600, 2601, Canberra, A.C.T., Australia.
authors.forename: T J
authors.initials: TJ
authors.lastname: Higgins
authors.forename: L R
authors.initials: LR
authors.lastname: Beach
authors.forename: D
authors.initials: D
authors.lastname: Spencer
authors.forename: P M
authors.initials: PM
authors.lastname: Chandler
authors.forename: P J
authors.initials: PJ
authors.lastname: Randall
authors.forename: R J
authors.initials: RJ
authors.lastname: Blagrove
authors.forename: A A
authors.initials: AA
authors.lastname: Kortt
authors.forename: R E
authors.initials: RE
authors.lastname: Guthrie