1b2f
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PH AFFECTS GLU B13 SWITCHING AND SULFATE BINDING IN CUBIC INSULIN CRYSTALS (PH 6.98 COORDINATES)
OverviewOverview
Structures of porcine insulin crystals soaked in 1 M sodium sulfate at pH 5.00, 5.53, 5.80, 6.00, 6.16, 6.26, 6.35, 6.50, 6.98 and 9.00 have been determined at between 1.7 and 1.9 A resolution. GluB13 exhibits a single conformation at pH </= 5.80, two conformations between pH 6.00 and 6.98 and a single conformation at pH 9.00. Between pH 6.00 and 6.98, the conformation of GluB13 switches from one rotamer to another rotamer. Between pH 6.16 and 6.26, PheB1 undergoes a significant conformational change. By pH 9.00 many residues have undergone relatively large shifts and HisB10 exhibits a double conformation. As a result of the pH increase, the occupancy of the sulfate ion decreases from a maximum of 1.00 at pH 5.00 to a minimum of 0.46 at pH 6.50. Comparison of the structures, the observed and calculated structure factors and map correlation coefficients indicate that the porcine insulin structure changes gradually as a function of pH.
About this StructureAbout this Structure
1B2F is a Protein complex structure of sequences from Sus scrofa. Full crystallographic information is available from OCA.
ReferenceReference
Crystallographic titration of cubic insulin crystals: pH affects GluB13 switching and sulfate binding., Diao J, Acta Crystallogr D Biol Crystallogr. 2003 Apr;59(Pt 4):670-6. Epub 2003, Mar 25. PMID:12657786
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