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PDBsum entry 1b2a
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Hormone/growth factor
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PDB id
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1b2a
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Crystallographic titration of cubic insulin crystals: ph affects glub13 switching and sulfate binding.
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Author
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J.Diao.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2003,
59,
670-676.
[DOI no: ]
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PubMed id
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Abstract
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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.
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Figure 2.
Figure 2 Structures at ten different pH and corresponding 2F[o]
- F[c] maps. Structures in the region of GluB13 and the sulfate
ion are presented and 2F[o] - F[c] maps are contoured at the 0.8
 level
because of the approximate half-occupancy of the two rotamers of
GluB13 and the lower electron density compared with the rest of
the structure. Sub-figures correspond to the structures at pH
5.00, 5.53, 5.80, 6.00, 6.16, 6.26, 6.35, 6.50, 6.98 and 9.00,
respectively.
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Figure 4.
Figure 4 Sulfate-binding region. The coordinates at pH 5.00 were
used to produce the figure.
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(2003,
59,
670-676)
copyright 2003.
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Secondary reference #1
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Title
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Conformational changes in cubic insulin crystals in the ph range 7-11.
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Authors
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O.Gursky,
J.Badger,
Y.Li,
D.L.Caspar.
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Ref.
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Biophys J, 1992,
63,
1210-1220.
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PubMed id
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Secondary reference #2
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Title
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Monovalent cation binding to cubic insulin crystals.
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Authors
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O.Gursky,
Y.Li,
J.Badger,
D.L.Caspar.
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Ref.
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Biophys J, 1992,
61,
604-611.
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PubMed id
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Secondary reference #3
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Title
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Flexibility in crystalline insulins.
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Author
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J.Badger.
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Ref.
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Biophys J, 1992,
61,
816-819.
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PubMed id
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Secondary reference #4
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Title
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Structure of the pig insulin dimer in the cubic crystal.
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Authors
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J.Badger,
M.R.Harris,
C.D.Reynolds,
A.C.Evans,
E.J.Dodson,
G.G.Dodson,
A.C.North.
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Ref.
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Acta Crystallogr B, 1991,
47,
127-136.
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PubMed id
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Secondary reference #5
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Title
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Water structure in cubic insulin crystals.
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Authors
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J.Badger,
D.L.Caspar.
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Ref.
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Proc Natl Acad Sci U S A, 1991,
88,
622-626.
[DOI no: ]
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PubMed id
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Secondary reference #6
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Title
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Zinc-Free cubic pig insulin: crystallization and structure determination.
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Authors
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E.J.Dodson,
G.G.Dodson,
A.Lewitova,
M.Sabesan.
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Ref.
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J Mol Biol, 1978,
125,
387-396.
[DOI no: ]
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PubMed id
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Figure 6.
FIG. 6. Average Sim-type weights (in y/,) against 4 sin2 B/AZ.
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Figure 8.
FIG 8. Schematic diagram of the arrangement of insulin molecule in the 23,3 unit cell. It'or
convenience, each oval represents a symmetrical insulin dimor.
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The above figures are
reproduced from the cited reference
with permission from Elsevier
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