title: Primary structure of rabbit lens alpha-crystallins.
abstract: The primary structure and posttranslational modifications of rabbit lens alpha-crystallins were examined using electrospray ionization mass spectrometry to determine the molecular weights of the intact proteins and fast atom bombardment mass spectrometry to analyze proteolytic digests of the alpha A- and alpha B-crystallins. The previously determined primary structure of alpha A-crystallin was confirmed. Posttranslational modifications detected included one phosphorylation site and the presence of a truncated form minus the five C-terminal residues. The previously undetermined amino acid sequence of rabbit alpha B-crystallin was determined to be the same as the bovine alpha B-crystallin sequence except at three residues: Thr 40, Thr 132, and Pro 153. Rabbit alpha B-crystallin showed evidence of phosphorylation at the same three sites as bovine alpha B-crystallin. The molecular weights of the intact proteins indicated that any one molecule had a maximum of two phosphorylations. Also, there was a truncated form which did not include the five C-terminal residues.
authors.affiliation: Department of Chemistry, Bahauddin Zakariya University, Multan, Pakistan.
authors.forename: R
authors.initials: R
authors.lastname: Parveen
authors.forename: J B
authors.initials: JB
authors.lastname: Smith
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
authors.forename: D L
authors.initials: DL
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003459:Crystallins / Q000737:chemistry* / Q000378:metabolism; D007908:Lens, Crystalline / Q000737:chemistry*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011817:Rabbits; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D003459:Crystallins