1THU

THE STRUCTURES OF THREE CRYSTAL FORMS OF THE SWEET PROTEIN THAUMATIN

Summary for 1THU

• Entry DOI: 10.2210/pdb1thu/pdb
• Descriptor: THAUMATIN ISOFORM B (1 entity in total)
• Functional Keywords: sweet tasting protein
• Biological source: Thaumatococcus daniellii (miracle fruit)
• Cellular location: Cytoplasmic vesicle: P02883
• Total number of polymer chains: 1
• Total formula weight: 22243.12

Authors

Ko, T.-P.,Day, J.,Greenwood, A.,McPherson, A. (deposition date: 1994-06-10, release date: 1994-12-20, Last modification date: 2024-06-05)

Primary citation

Ko, T.P.,Day, J.,Greenwood, A.,McPherson, A.
Structures of three crystal forms of the sweet protein thaumatin.
Acta Crystallogr.,Sect.D, 50:813-825, 1994

PubMed Abstract: Three crystal forms of the sweet-tasting protein thaumatin from the African berry Thaumatococcus daniellii have been grown. These include two naturally occurring isoforms, A and B, that differ by a single amino acid, and a recombinant form of isoform B expressed in yeast. The crystals are of space groups C2 with a = 117.7, b = 44.9, c = 38.0 A, and beta = 94.0 degrees, P2(1)2(1)2(1) with a = 44.3, b = 63.7 and c = 72.7 A, and a tetragonal form P4(1)2(1)2 with a = b = 58.6 and c = 151.8 A. The structures of all three crystals have been solved by molecular replacement and subsequently refined to R factors of 0.184 for the monoclinic at 2.6 A, 0.165 for the orthorhombic at 1.75 A, and 0.181 for the tetragonal, also at 1.75 A resolution. No solvent was included in the monoclinic crystal while 123 and 105 water molecules were included in the higher resolution orthorhombic and tetragonal structures, respectively. A bound tartrate molecule was also clearly visible in the tetragonal structure. The r.m.s. deviations between molecular structures in the three crystals range from 0.6 to 0.7 A for Calpha atoms, and 1.1 to 1.3 A for all atoms. This is comparable to the r.m.s. deviation between the three structures and the starting model. Nevertheless, several peptide loops show particularly large variations from the initial model.

PubMed: 15299348
DOI: 10.1107/S0907444994005512

Experimental method

X-RAY DIFFRACTION (2.6 Å)