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PDBsum entry 1py3
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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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Crystal structure reveals two alternative conformations in the active site of ribonuclease sa2.
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Authors
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J.Sevcík,
Z.Dauter,
K.S.Wilson.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2004,
60,
1198-1204.
[DOI no: ]
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PubMed id
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Abstract
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Three different strains of Streptomyces aureofaciens produce the homologous
ribonucleases Sa, Sa2 and Sa3. The crystal structures of ribonuclease Sa (RNase
Sa) and its complexes with mononucleotides have previously been reported at high
resolution. Here, the structures of two crystal forms (I and II) of ribonuclease
Sa2 (RNase Sa2) are presented at 1.8 and 1.5 A resolution. The structures were
determined by molecular replacement using the coordinates of RNase Sa as a
search model and were refined to R factors of 17.5 and 15.0% and R(free) factors
of 21.8 and 17.2%, respectively. The asymmetric unit of crystal form I contains
three enzyme molecules, two of which have similar structures to those seen for
ribonuclease Sa, with Tyr87 at the bottom of their active sites. In the third
molecule, Tyr87 has moved substantially: the CA atom moves almost 5 A and the OH
of the side chain moves 10 A, inserting itself into the active site of a
neighbouring molecule at a similar position to that observed for the nucleotide
base in RNase Sa complexes. The asymmetric unit of crystal form II contains two
Sa2 molecules, both of which are similar to the usual Sa structures. In one
molecule, two main-chain conformations were modelled in the alpha-helix.
Finally, a brief comparison is made between the conformations of the Sa2
molecules and those of 34 independent molecules taken from 20 structures of
ribonuclease Sa and two independent molecules taken from two structures of
ribonuclease Sa3 in various crystal forms.
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Secondary reference #1
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Title
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Purification of ribonucleases sa, Sa2, And sa3 after expression in escherichia coli.
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Authors
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E.J.Hebert,
G.R.Grimsley,
R.W.Hartley,
G.Horn,
D.Schell,
S.Garcia,
V.Both,
J.Sevcik,
C.N.Pace.
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Ref.
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Protein Expr Purif, 1997,
11,
162-168.
[DOI no: ]
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PubMed id
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