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| [PMID]: | 25046564 |
| [Au] Autor: | Chao WC; Shen JY; Lu JF; Wang JS; Yang HC; Wee K; Lin LJ; Kuo YC; Yang CH; Weng SH; Huang HC; Chen YH; Chou PT |
| [Ad] Endereço: | Department of Chemistry and Center for Emerging Material and Advanced Devices, National Taiwan University , Taipei 10617, Taiwan. |
| [Ti] Título: | Probing water environment of Trp59 in ribonuclease T1: insight of the structure-water network relationship. |
| [So] Source: | J Phys Chem B;119(6):2157-67, 2015 Feb 12. | | [Is] ISSN: | 1520-5207 |
| [Cp] País de publicação: | United States |
| [La] Idioma: | eng |
| [Ab] Resumo: | In this study, we used the tryptophan analogue, (2,7-aza)Trp, which exhibits water catalyzed proton transfer isomerization among N(1)-H, N(7)-H, and N(2)-H isomers, to probe the water environment of tryptophan-59 (Trp59) near the connecting loop region of ribonuclease Tl (RNase T1) by replacing the tryptophan with (2,7-aza)Trp. The resulting (2,7-aza)Trp59 triple emission bands and their associated relaxation dynamics, together with relevant data of 7-azatryptophan and molecular dynamics (MD) simulation, lead us to propose two Trp59 containing conformers in RNase T1, namely, the loop-close and loop-open forms. Water is rich in the loop-open form around the proximity of (2,7-aza)Trp59, which catalyzes (2,7-aza)Trp59 proton transfer in the excited state, giving both N(1)-H and N(7)-H isomer emissions. The existence of N(2)-H isomer in the loop-open form, supported by the MD simulation, is mainly due to the specific hydrogen bonding between N(2)-H proton and water molecule that bridges N(2)-H and the amide oxygen of Pro60, forming a strong network. The loop-close form is relatively tight in space, which squeezes water molecules out of the interface of α-helix and ß2 strand, joined by the connecting loop region; accordingly, the water-scant environment leads to the sole existence of the N(1)-H isomer emission. MD simulation also points out that the Trp-water pairs appear to preferentially participate in a hydrogen bond network incorporating polar amino acid moieties on the protein surface and bulk waters, providing the structural dynamic features of the connecting loop region in RNase T1. |
| [Mh] Termos MeSH primário: |
Ribonuclease T1/química
Água/química
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| [Mh] Termos MeSH secundário: |
Substituição de Aminoácidos
Aspergillus oryzae/enzimologia
Ligações de Hidrogênio
Simulação de Dinâmica Molecular
Estrutura Secundária de Proteína
Ribonuclease T1/genética
Triptofano
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| [Pt] Tipo de publicação: | JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T |
[Nm] Nome de substância:
| 059QF0KO0R (Water); 8DUH1N11BX (Tryptophan); EC 3.1.27.3 (Ribonuclease T1) |
| [Em] Mês de entrada: | 1602 |
| [Cu] Atualização por classe: | 150212 |
[Lr] Data última revisão:
| 150212 |
| [Sb] Subgrupo de revista: | IM |
| [Da] Data de entrada para processamento: | 140722 |
| [St] Status: | MEDLINE |
| [do] DOI: | 10.1021/jp503914s |
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