3AA2
A52I E. coli RNase HI
Summary for 3AA2
| Entry DOI | 10.2210/pdb3aa2/pdb |
| Related | 3AA3 3AA4 3AA5 |
| Descriptor | Ribonuclease HI (2 entities in total) |
| Functional Keywords | stability, cavity, endonuclease, hydrolase, magnesium, metal-binding, nuclease |
| Biological source | Escherichia coli |
| Cellular location | Cytoplasm : P0A7Y4 |
| Total number of polymer chains | 1 |
| Total formula weight | 17665.08 |
| Authors | Takano, K. (deposition date: 2009-11-11, release date: 2010-10-06, Last modification date: 2024-03-13) |
| Primary citation | Tanaka, M.,Chon, H.,Angkawidjaja, C.,Koga, Y.,Takano, K.,Kanaya, S. Protein core adaptability: crystal structures of the cavity-filling variants of Escherichia coli RNase HI Protein Pept.Lett., 17:1163-1169, 2010 Cited by PubMed Abstract: It has generally been accepted that an increase in protein stability is proportional to the increase in hydrophobicity. When a cavity is created by large-to-small substitutions of amino acid residues in protein cores, protein stability decreases 5.3 kJ/mol per single methyl(ene) group removal. In contrast, many reported cavity-filling mutations either failed to increase stability or produced marginal increases in stability; even in successful cases, the increase in stability was much lower than expected from the cost of single methyl(ene) group removal in cavity-creating mutations. Previously it was found that some cavity-filling mutant proteins at Ala52 in E. coli RNase HI increased stability, but decreased activity and they did not increase the stability to the degree expected by the hydrophobic effect alone. The present study attempted to structurally analyze these variant proteins, and it was found that substitutions have little effect on the overall fold but cause conformational strains with the neighboring residues. The present results and literature on cavity-creating/-filling variants provide insight into protein architecture, indicating that natural protein cores are able to accommodate larger side-chain residue by substitution; in other words, excess-packing may not be chosen in natural selection. PubMed: 20423323DOI: 10.2174/092986610791760342 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.9 Å) |
Structure validation
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