Functional role for Tyr 31 in the Catalytic cycle of Chicken Dihydrofolate Reductase

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Functional role for Tyr 31 in the Catalytic cycle of Chicken Dihydrofolate Reductase. / [No Value], [No Value]; Mullaney, A; Allemann, Rudolf.

In: Proteins: structure, function, and bioinformatics , Vol. 51, No. 2, 01.05.2003, p. 216-223.

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@article{50440435582041e1a44609b20bdb7b29,
title = "Functional role for Tyr 31 in the Catalytic cycle of Chicken Dihydrofolate Reductase",
abstract = "Despite much work, many key aspects of the mechanism of the dihydrofolate reductase (DHFR) catalyzed reduction of dihydrofolate remain unresolved. In bacterial forms of DHFR both substrate and water access to the active site are controlled by the conformation of the mobile M20 loop. In vertebrate DHFRs only one conformation of the residues corresponding to the M20 loop has been observed. Access to the active site was proposed to be controlled by residue 31. MD simulations of chicken DHFR complexed with substrates and cofactor revealed a closing of the side chain of Tyr 31 over the active site on binding of dihydrofolate. This conformational change was dependent on the presence of glutamate on the para-aminobenzoylamide moiety of dihydrofolate. In its absence, the conformation remained open. Although water could enter the active site and hydrogen bond to N5 of dihydrofolate, indicating the feasibility of water as the proton donor, this was not controlled by the conformation of Tyr 31. The water accessibility of the active site was low for both conformations of Tyr 31. However, when hydride was transferred from NADPH to C6 of dihydrofolate before protonation, the average time during which water was found in hydrogen bonding distance to N5 of dihydrofolate in the active site increased almost fivefold. These results indicated that water can serve as the Broensted acid for the protonation of N5 of dihydrofolate during the DHFR catalyzed reduction. (C) 2003 Wiley-Liss, Inc.",
author = "{[No Value]}, {[No Value]} and A Mullaney and Rudolf Allemann",
year = "2003",
month = may
day = "1",
doi = "10.1002/prot.10370",
language = "English",
volume = "51",
pages = "216--223",
journal = "Proteins: structure, function, and bioinformatics ",
issn = "0887-3585",
publisher = "Wiley",
number = "2",

}

RIS

TY - JOUR

T1 - Functional role for Tyr 31 in the Catalytic cycle of Chicken Dihydrofolate Reductase

AU - [No Value], [No Value]

AU - Mullaney, A

AU - Allemann, Rudolf

PY - 2003/5/1

Y1 - 2003/5/1

N2 - Despite much work, many key aspects of the mechanism of the dihydrofolate reductase (DHFR) catalyzed reduction of dihydrofolate remain unresolved. In bacterial forms of DHFR both substrate and water access to the active site are controlled by the conformation of the mobile M20 loop. In vertebrate DHFRs only one conformation of the residues corresponding to the M20 loop has been observed. Access to the active site was proposed to be controlled by residue 31. MD simulations of chicken DHFR complexed with substrates and cofactor revealed a closing of the side chain of Tyr 31 over the active site on binding of dihydrofolate. This conformational change was dependent on the presence of glutamate on the para-aminobenzoylamide moiety of dihydrofolate. In its absence, the conformation remained open. Although water could enter the active site and hydrogen bond to N5 of dihydrofolate, indicating the feasibility of water as the proton donor, this was not controlled by the conformation of Tyr 31. The water accessibility of the active site was low for both conformations of Tyr 31. However, when hydride was transferred from NADPH to C6 of dihydrofolate before protonation, the average time during which water was found in hydrogen bonding distance to N5 of dihydrofolate in the active site increased almost fivefold. These results indicated that water can serve as the Broensted acid for the protonation of N5 of dihydrofolate during the DHFR catalyzed reduction. (C) 2003 Wiley-Liss, Inc.

AB - Despite much work, many key aspects of the mechanism of the dihydrofolate reductase (DHFR) catalyzed reduction of dihydrofolate remain unresolved. In bacterial forms of DHFR both substrate and water access to the active site are controlled by the conformation of the mobile M20 loop. In vertebrate DHFRs only one conformation of the residues corresponding to the M20 loop has been observed. Access to the active site was proposed to be controlled by residue 31. MD simulations of chicken DHFR complexed with substrates and cofactor revealed a closing of the side chain of Tyr 31 over the active site on binding of dihydrofolate. This conformational change was dependent on the presence of glutamate on the para-aminobenzoylamide moiety of dihydrofolate. In its absence, the conformation remained open. Although water could enter the active site and hydrogen bond to N5 of dihydrofolate, indicating the feasibility of water as the proton donor, this was not controlled by the conformation of Tyr 31. The water accessibility of the active site was low for both conformations of Tyr 31. However, when hydride was transferred from NADPH to C6 of dihydrofolate before protonation, the average time during which water was found in hydrogen bonding distance to N5 of dihydrofolate in the active site increased almost fivefold. These results indicated that water can serve as the Broensted acid for the protonation of N5 of dihydrofolate during the DHFR catalyzed reduction. (C) 2003 Wiley-Liss, Inc.

UR - http://www.scopus.com/inward/record.url?scp=0037402111&partnerID=8YFLogxK

U2 - 10.1002/prot.10370

DO - 10.1002/prot.10370

M3 - Article

VL - 51

SP - 216

EP - 223

JO - Proteins: structure, function, and bioinformatics

JF - Proteins: structure, function, and bioinformatics

SN - 0887-3585

IS - 2

ER -