1g7b
From Proteopedia
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[[Image:1g7b.gif|left|200px]] | [[Image:1g7b.gif|left|200px]] | ||
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'''1.3 A STRUCTURE OF T3R3 HUMAN INSULIN AT 100 K''' | '''1.3 A STRUCTURE OF T3R3 HUMAN INSULIN AT 100 K''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1G7B is a [[Protein complex]] structure | + | 1G7B is a [[Protein complex]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G7B OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Pangborn, W A.]] | [[Category: Pangborn, W A.]] | ||
[[Category: Smith, G D.]] | [[Category: Smith, G D.]] | ||
| - | [[Category: | + | [[Category: T3r3 human insulin hexamer]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:13:56 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 14:13, 2 May 2008
1.3 A STRUCTURE OF T3R3 HUMAN INSULIN AT 100 K
Overview
The structure of T(3)R(3) hexameric human insulin has been determined at 100 K from two different crystals at 1.2 and 1.3 A resolution and refined to residuals of 0.169 and 0.176, respectively. Owing to a phase change, the c axis is double its room-temperature value and the asymmetric unit contains two independent TR(f) insulin dimers. Compared with the orientation in the room-temperature structure, one dimer undergoes a rotation about the c axis of -5 degrees, while the second is rotated +4 degrees. A superposition of the backbone atoms of the two independent dimers shows that the C(alpha) atoms of five residues within the R(f)-state monomers are displaced by more than 1.0 A; smaller displacements are observed for the T-state monomers. Four zinc ions lie on the crystallographic threefold axis and each forms bonds to three symmetry-related HisB10 N(varepsilon2) atoms from the T- and R(f)-state trimers. While three of the zinc ions are tetrahedrally coordinated with a chloride ion completing the coordination sphere, mixed tetrahedral/octahedral coordination is observed for one of the T-state zinc ions. The three symmetry-related "phenolic binding sites" in one hexamer contain water molecules and a glycerol molecule, but the same sites in the second hexamer are occupied by a zinc ion coordinated to an alternate conformation of HisB10, a symmetry-related HisB5 and two chloride ions. Two additional and partially occupied zinc ion sites are observed at the interface between the two independent dimers. One zinc ion is coordinated by a T-state HisB5 of one dimer, an R-state HisB5 of the second dimer and two water molecules; the second zinc ion is coordinated by an alternate side-chain conformation of the T-state HisB5 and three water molecules. The carboxyl group of one GluB13 side chain, which exists in two discrete conformations, appears to be protonated, because short contacts exist to a second carboxyl group or to a carbonyl O atom.
About this Structure
1G7B is a Protein complex structure. Full crystallographic information is available from OCA.
Reference
Phase changes in T(3)R(3)(f) human insulin: temperature or pressure induced?, Smith GD, Pangborn WA, Blessing RH, Acta Crystallogr D Biol Crystallogr. 2001 Aug;57(Pt 8):1091-100. Epub 2001, Jul 23. PMID:11468392 Page seeded by OCA on Fri May 2 17:13:56 2008
