2XAX の概要
| エントリーDOI | 10.2210/pdb2xax/pdb |
| 関連するPDBエントリー | 1AV8 1BIQ 1JPR 1JQC 1MRR 1MXR 1PFR 1PIM 1PIU 1PIY 1PIZ 1PJ0 1PJ1 1PM2 1QFN 1R1R 1R65 1RIB 1RLR 1RNR 1RSR 1RSV 1XIK 1YFD 2ALX 2AV8 2R1R 2X0X 2XAK 2XAP 2XAV 2XAW 2XAY 2XAZ 3R1R 4R1R 5R1R 6R1R 7R1R |
| 分子名称 | RIBONUCLEOSIDE-DIPHOSPHATE REDUCTASE 1 SUBUNIT ALPHA, RIBONUCLEOSIDE-DIPHOSPHATE REDUCTASE 1 SUBUNIT BETA (3 entities in total) |
| 機能のキーワード | oxidoreductase, nucleotide-binding, alternative initiation, dna replication, allosteric enzyme |
| 由来する生物種 | ESCHERICHIA COLI 詳細 |
| タンパク質・核酸の鎖数 | 7 |
| 化学式量合計 | 266575.54 |
| 構造登録者 | |
| 主引用文献 | Yokoyama, K.,Uhlin, U.,Stubbe, J. Site-Specific Incorporation of 3-Nitrotyrosine as a Probe of Pk(A) Perturbation of Redox-Active Tyrosines in Ribonucleotide Reductase. J.Am.Chem.Soc., 132:8385-, 2010 Cited by PubMed Abstract: E. coli ribonucleotide reductase catalyzes the reduction of nucleoside 5'-diphosphates into 2'-deoxynucleotides and is composed of two subunits: alpha2 and beta2. During turnover, a stable tyrosyl radical (Y*) at Y(122)-beta2 reversibly oxidizes C(439) in the active site of alpha2. This radical propagation step is proposed to occur over 35 A, to use specific redox-active tyrosines (Y(122) and Y(356) in beta2, Y(731) and Y(730) in alpha2), and to involve proton-coupled electron transfer (PCET). 3-Nitrotyrosine (NO(2)Y, pK(a) 7.1) has been incorporated in place of Y(122), Y(731), and Y(730) to probe how the protein environment perturbs each pK(a) in the presence of the second subunit, substrate (S), and allosteric effector (E). The activity of each mutant is <4 x 10(-3) that of the wild-type (wt) subunit. The [NO(2)Y(730)]-alpha2 and [NO(2)Y(731)]-alpha2 each exhibit a pK(a) of 7.8-8.0 with E and E/beta2. The pK(a) of [NO(2)Y(730)]-alpha2 is elevated to 8.2-8.3 in the S/E/beta2 complex, whereas no further perturbation is observed for [NO(2)Y(731)]-alpha2. Mutations in pathway residues adjacent to the NO(2)Y that disrupt H-bonding minimally perturb its pK(a). The pK(a) of NO(2)Y(122)-beta2 alone or with alpha2/S/E is >9.6. X-ray crystal structures have been obtained for all [NO(2)Y]-alpha2 mutants (2.1-3.1 A resolution), which show minimal structural perturbation compared to wt-alpha2. Together with the pK(a) of the previously reported NO(2)Y(356)-beta2 (7.5 in the alpha2/S/E complex; Yee, C. et al. Biochemistry 2003, 42, 14541-14552), these studies provide a picture of the protein environment of the ground state at each Y in the PCET pathway, and are the starting point for understanding differences in PCET mechanisms at each residue in the pathway. PubMed: 20518462DOI: 10.1021/JA101097P 主引用文献が同じPDBエントリー |
| 実験手法 | X-RAY DIFFRACTION (2.75 Å) |
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