title: A novel 40 kDa protein from goat mammary secretions: purification, crystallization and preliminary X-ray diffraction studies.
abstract: A novel 40 kDa protein has been purified from dry secretions of the mammary gland of goats. The first 15 N-terminal residues were sequenced and showed a sequence identity of 30% to a novel 39 kDa whey protein from bovine mammary secretions. The protein was crystallized by the microdialysis method. Protein was dissolved to a concentration of 40 mg ml(-1) in 0.025 M Tris-HCl pH 8.0 and equilibrated with the same buffer containing 19%(v/v) ethanol. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 66.1, b = 107.8, c = 63.2 A and one molecule per asymmetric unit. Intensity data were collected to 2.9 A resolution, with a completeness of 95%. Since no similar model is available in the protein structure database, heavy-atom derivatives have been prepared and three-dimensional structure determination using the isomorphous replacement method is in progress.
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110 029, India.
authors.forename: P
authors.initials: P
authors.lastname: Kumar
authors.forename: S
authors.initials: S
authors.lastname: Yadav
authors.forename: A
authors.initials: A
authors.lastname: Srinivasan
authors.forename: K L
authors.initials: KL
authors.lastname: Bhatia
authors.forename: T P
authors.initials: TP
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003460:Crystallization; D018360:Crystallography, X-Ray; D006041:Goats; D008321:Mammary Glands, Animal / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry; D008970:Molecular Weight; D011487:Protein Conformation; D020539:Sequence Analysis, Protein; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins