title: Secondary structure of bovine alphaS2-casein: theoretical and experimental approaches.
abstract: Circular dichroism and Fourier transform infrared spectroscopy of bovine alphaS2-casein both report a 24 to 32% content of alpha-helix. A consensus of sequence based predictions for alpha-helix suggests a Lys77-Gln91 helix within the sequence (Ser61-Arg125). This motif is repeated at (Ser143-Leu207), and this region contains a longer Thr145-Leu177 predicted alpha-helix. A short, seven-member alpha-helix may also organize the N-terminal peptide that precedes the first phosphoserine [-Srp-]3 cluster. As was found for other caseins studied by these spectroscopic methods, a high degree of extended beta-sheet (approximately 30%) and turns (25 to 30%) are predicted for alphaS2-casein.
authors.affiliation: U. S. Department of Agriculture, Agriculture Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA. phoagland@arserrc.gov
authors.forename: P D
authors.initials: PD
authors.lastname: Hoagland
authors.forename: J J
authors.initials: JJ
authors.lastname: Unruh
authors.forename: E D
authors.initials: ED
authors.lastname: Wickham
authors.forename: H M
authors.initials: HM
authors.lastname: Farrell
mesh_terms: D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D002942:Circular Dichroism; D008823:Micelles; D008892:Milk / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods / Q000662:veterinary
chemical_list: D002364:Caseins; D008823:Micelles; D010446:Peptide Fragments