1un4
From Proteopedia
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| - | | | + | {{STRUCTURE_1un4| PDB=1un4 | SCENE= }} |
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'''CRYSTAL STRUCTURE OF HUMAN ANGIOGENIN VARIANT T80A''' | '''CRYSTAL STRUCTURE OF HUMAN ANGIOGENIN VARIANT T80A''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1UN4 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry | + | 1UN4 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1h0e 1h0e]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UN4 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Chavali, G B.]] | [[Category: Chavali, G B.]] | ||
[[Category: Holloway, D E.]] | [[Category: Holloway, D E.]] | ||
| - | [[Category: | + | [[Category: Angiogenesis]] |
| - | [[Category: | + | [[Category: Endonuclease]] |
| - | [[Category: | + | [[Category: Hydrolase]] |
| - | [[Category: | + | [[Category: Nuclease]] |
| - | [[Category: | + | [[Category: Pyrrolidone carboxylic acid]] |
| - | [[Category: | + | [[Category: Ribonuclease]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 11:27:18 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 08:27, 3 May 2008
CRYSTAL STRUCTURE OF HUMAN ANGIOGENIN VARIANT T80A
Overview
Human angiogenin (Ang) is a potent inducer of blood vessel formation and is a member of the pancreatic ribonuclease superfamily. Its enzymatic activity is unusually weak and biased toward cleavage after cytidine nucleotides. As part of an ongoing investigation into the structural basis of Ang's characteristic activity, we have determined the crystal structures of three Ang variants having novel activity. (i) The structure of T44D-Ang indicates that Asp44 can participate directly in pyrimidine binding and that the intrinsic hydrogen-bonding capability of this residue largely governs the pyrimidine specificity of this variant. Unexpectedly, the mutation also causes the most extensive disruption of the C-terminus seen in any Ang variant thus far. This allows the side chain of Arg101 to penetrate the B(1) site, raising the possibility that it participates in substrate binding as occurs in ribonuclease 4. (ii) The structure of T80A-Ang supports the view that Thr80 plays little role in maintaining the obstructive conformation of the C-terminus and that its participation in a hydrogen bond with Thr44 selectively weakens the interaction between Thr44 and N3 of cytosine. (iii) ARH-II is an angiogenin/RNase A chimera in which residues 38-41 of Ang are replaced with the corresponding residues (38-42) of RNase A. Its structure suggests that the guest segment influences catalysis by subtle means, possibly by reducing the pK(a) of the catalytic lysine. The loss of angiogenic activity is not attributable to disruption of known cell-binding or nuclear translocation sites but may be a consequence of the chimera's enhanced ribonucleolytic activity.
About this Structure
1UN4 is a Single protein structure of sequence from Homo sapiens. This structure supersedes the now removed PDB entry 1h0e. Full crystallographic information is available from OCA.
Reference
Crystallographic studies on structural features that determine the enzymatic specificity and potency of human angiogenin: Thr44, Thr80, and residues 38-41., Holloway DE, Chavali GB, Hares MC, Baker MD, Subbarao GV, Shapiro R, Acharya KR, Biochemistry. 2004 Feb 10;43(5):1230-41. PMID:14756559 Page seeded by OCA on Sat May 3 11:27:18 2008
