1z7x: Difference between revisions
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
==Overview== | ==Overview== | ||
The ribonuclease inhibitor protein (RI) binds to members of the bovine, pancreatic ribonuclease (RNase A) superfamily with an affinity in the, femtomolar range. Here, we report on structural and energetic aspects of, the interaction between human RI (hRI) and human pancreatic ribonuclease, (RNase 1). The structure of the crystalline hRI x RNase 1 complex was, determined at a resolution of 1.95 A, revealing the formation of 19, intermolecular hydrogen bonds involving 13 residues of RNase 1. In, contrast, only nine such hydrogen bonds are apparent in the structure of, the complex between porcine RI and RNase A. hRI, which is anionic, also, appears to use its horseshoe-shaped structure to engender long-range, Coulombic interactions with RNase 1, which is cationic. In accordance with, the structural data, the hRI.RNase 1 complex was found to be extremely, stable (t(1/2)=81 days; K(d)=2.9 x 10(-16) M). Site-directed mutagenesis, experiments enabled the identification of two cationic residues in RNase, 1, Arg39 and Arg91, that are especially important for both the formation, and stability of the complex, and are thus termed "electrostatic targeting, residues". Disturbing the electrostatic attraction between hRI and RNase 1, yielded a variant of RNase 1 that maintained ribonucleolytic activity and, conformational stability but had a 2.8 x 10(3)-fold lower association rate, for complex formation and 5.9 x 10(9)-fold lower affinity for hRI. This, variant of RNase 1, which exhibits the largest decrease in RI affinity of, any engineered ribonuclease, is also toxic to human erythroleukemia cells., Together, these results provide new insight into an unusual and important, protein-protein interaction, and could expedite the development of human, ribonucleases as chemotherapeutic agents. | The ribonuclease inhibitor protein (RI) binds to members of the bovine, pancreatic ribonuclease (RNase A) superfamily with an affinity in the, femtomolar range. Here, we report on structural and energetic aspects of, the interaction between human RI (hRI) and human pancreatic ribonuclease, (RNase 1). The structure of the crystalline hRI x RNase 1 complex was, determined at a resolution of 1.95 A, revealing the formation of 19, intermolecular hydrogen bonds involving 13 residues of RNase 1. In, contrast, only nine such hydrogen bonds are apparent in the structure of, the complex between porcine RI and RNase A. hRI, which is anionic, also, appears to use its horseshoe-shaped structure to engender long-range, Coulombic interactions with RNase 1, which is cationic. In accordance with, the structural data, the hRI.RNase 1 complex was found to be extremely, stable (t(1/2)=81 days; K(d)=2.9 x 10(-16) M). Site-directed mutagenesis, experiments enabled the identification of two cationic residues in RNase, 1, Arg39 and Arg91, that are especially important for both the formation, and stability of the complex, and are thus termed "electrostatic targeting, residues". Disturbing the electrostatic attraction between hRI and RNase 1, yielded a variant of RNase 1 that maintained ribonucleolytic activity and, conformational stability but had a 2.8 x 10(3)-fold lower association rate, for complex formation and 5.9 x 10(9)-fold lower affinity for hRI. This, variant of RNase 1, which exhibits the largest decrease in RI affinity of, any engineered ribonuclease, is also toxic to human erythroleukemia cells., Together, these results provide new insight into an unusual and important, protein-protein interaction, and could expedite the development of human, ribonucleases as chemotherapeutic agents. | ||
==Disease== | |||
Known diseases associated with this structure: Aicardi-Goutieres syndrome 4 OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=606034 606034]], Creutzfeldt-Jakob disease OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176640 176640]], Gerstmann-Straussler disease OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176640 176640]], Huntington disease-like 1 OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176640 176640]], Insomnia, fatal familial OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176640 176640]], Prion disease with protracted course OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176640 176640]] | |||
==About this Structure== | ==About this Structure== | ||
1Z7X is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=CIT:'>CIT</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Pancreatic_ribonuclease Pancreatic ribonuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.5 3.1.27.5] Known structural/functional Site: <scene name='pdbsite=AC1:Cit Binding Site For Residue X 900'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Z7X OCA]. | 1Z7X is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=CIT:'>CIT</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Pancreatic_ribonuclease Pancreatic ribonuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.5 3.1.27.5] Known structural/functional Site: <scene name='pdbsite=AC1:Cit+Binding+Site+For+Residue+X+900'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Z7X OCA]. | ||
==Reference== | ==Reference== | ||
| Line 18: | Line 21: | ||
[[Category: Bitto, E.]] | [[Category: Bitto, E.]] | ||
[[Category: CESG, Center.for.Eukaryotic.Structural.Genomics.]] | [[Category: CESG, Center.for.Eukaryotic.Structural.Genomics.]] | ||
[[Category: Johnson, R.J.]] | |||
[[Category: Jr., G.N.Phillips.]] | [[Category: Jr., G.N.Phillips.]] | ||
[[Category: McCoy, J.G.]] | [[Category: McCoy, J.G.]] | ||
[[Category: Raines, R.T.]] | |||
[[Category: Wesenberg, G.E.]] | [[Category: Wesenberg, G.E.]] | ||
[[Category: CIT]] | [[Category: CIT]] | ||
| Line 32: | Line 37: | ||
[[Category: structural genomics]] | [[Category: structural genomics]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Feb 13 08:16:47 2008'' | ||