Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase

Bogumil Zelent, Chris Bialas, Ignacy Gryczynski, Pan Chen, Rahul Chib, Karina Lewerissa, Maria G. Corradini, Richard D. Ludescher, Jane M. Vanderkooi, Franz M. Matschinsky

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Five variants of glucokinase (ATP-D-hexose-6-phosphotransferase, EC 2.7.1.1) including wild type and single Trp mutants with the Trp residue at positions 65, 99, 167 and 257 were prepared. The fluorescence of Trp in all locations studied showed intensity changes when glucose bound, indicating that conformational change occurs globally over the entire protein. While the fluorescence quantum yield changes upon glucose binding, the enzyme’s absorption spectra, emission spectra and fluorescence lifetimes change very little. These results are consistent with the existence of a dark complex for excited state Trp. Addition of glycerol, L-glucose, sucrose, or trehalose increases the binding affinity of glucose to the enzyme and increases fluorescence intensity. The effect of these osmolytes is thought to shift the protein conformation to a condensed, high affinity form. Based upon these results, we consider the nature of quenching of the Trp excited state. Amide groups are known to quench indole fluorescence and amides of the polypeptide chain make interact with excited state Trp in the relatively unstructured, glucose-free enzyme. Also, removal of water around the aromatic ring by addition of glucose substrate or osmolyte may reduce the quenching.

Original languageEnglish
Pages (from-to)1621-1631
Number of pages11
JournalJournal of Fluorescence
Volume27
Issue number5
DOIs
StatePublished - 1 Sep 2017

Fingerprint

Glucokinase
Tryptophan
Fluorescence
Glucose
Excited states
European Community
Amides
water
Quenching
Enzymes
Protein Conformation
Trehalose
Hexokinase
Group
Quantum yield
Glycerol
Sucrose
Conformations
Absorption spectra
Proteins

Keywords

  • Aromatic groups
  • Dark complexes
  • Glucokinase
  • Glucose
  • Glycerol
  • Osmolites
  • Tryptophan fluorescence

Cite this

Zelent, Bogumil ; Bialas, Chris ; Gryczynski, Ignacy ; Chen, Pan ; Chib, Rahul ; Lewerissa, Karina ; Corradini, Maria G. ; Ludescher, Richard D. ; Vanderkooi, Jane M. ; Matschinsky, Franz M. / Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase. In: Journal of Fluorescence. 2017 ; Vol. 27, No. 5. pp. 1621-1631.
@article{e417d4f8cc554d31bad347932d4914ad,
title = "Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase",
abstract = "Five variants of glucokinase (ATP-D-hexose-6-phosphotransferase, EC 2.7.1.1) including wild type and single Trp mutants with the Trp residue at positions 65, 99, 167 and 257 were prepared. The fluorescence of Trp in all locations studied showed intensity changes when glucose bound, indicating that conformational change occurs globally over the entire protein. While the fluorescence quantum yield changes upon glucose binding, the enzyme’s absorption spectra, emission spectra and fluorescence lifetimes change very little. These results are consistent with the existence of a dark complex for excited state Trp. Addition of glycerol, L-glucose, sucrose, or trehalose increases the binding affinity of glucose to the enzyme and increases fluorescence intensity. The effect of these osmolytes is thought to shift the protein conformation to a condensed, high affinity form. Based upon these results, we consider the nature of quenching of the Trp excited state. Amide groups are known to quench indole fluorescence and amides of the polypeptide chain make interact with excited state Trp in the relatively unstructured, glucose-free enzyme. Also, removal of water around the aromatic ring by addition of glucose substrate or osmolyte may reduce the quenching.",
keywords = "Aromatic groups, Dark complexes, Glucokinase, Glucose, Glycerol, Osmolites, Tryptophan fluorescence",
author = "Bogumil Zelent and Chris Bialas and Ignacy Gryczynski and Pan Chen and Rahul Chib and Karina Lewerissa and Corradini, {Maria G.} and Ludescher, {Richard D.} and Vanderkooi, {Jane M.} and Matschinsky, {Franz M.}",
year = "2017",
month = "9",
day = "1",
doi = "10.1007/s10895-017-2099-x",
language = "English",
volume = "27",
pages = "1621--1631",
journal = "Journal of Fluorescence",
issn = "1053-0509",
publisher = "Springer New York",
number = "5",

}

Zelent, B, Bialas, C, Gryczynski, I, Chen, P, Chib, R, Lewerissa, K, Corradini, MG, Ludescher, RD, Vanderkooi, JM & Matschinsky, FM 2017, 'Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase', Journal of Fluorescence, vol. 27, no. 5, pp. 1621-1631. https://doi.org/10.1007/s10895-017-2099-x

Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase. / Zelent, Bogumil; Bialas, Chris; Gryczynski, Ignacy; Chen, Pan; Chib, Rahul; Lewerissa, Karina; Corradini, Maria G.; Ludescher, Richard D.; Vanderkooi, Jane M.; Matschinsky, Franz M.

In: Journal of Fluorescence, Vol. 27, No. 5, 01.09.2017, p. 1621-1631.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Tryptophan Fluorescence Yields and Lifetimes as a Probe of Conformational Changes in Human Glucokinase

AU - Zelent, Bogumil

AU - Bialas, Chris

AU - Gryczynski, Ignacy

AU - Chen, Pan

AU - Chib, Rahul

AU - Lewerissa, Karina

AU - Corradini, Maria G.

AU - Ludescher, Richard D.

AU - Vanderkooi, Jane M.

AU - Matschinsky, Franz M.

PY - 2017/9/1

Y1 - 2017/9/1

N2 - Five variants of glucokinase (ATP-D-hexose-6-phosphotransferase, EC 2.7.1.1) including wild type and single Trp mutants with the Trp residue at positions 65, 99, 167 and 257 were prepared. The fluorescence of Trp in all locations studied showed intensity changes when glucose bound, indicating that conformational change occurs globally over the entire protein. While the fluorescence quantum yield changes upon glucose binding, the enzyme’s absorption spectra, emission spectra and fluorescence lifetimes change very little. These results are consistent with the existence of a dark complex for excited state Trp. Addition of glycerol, L-glucose, sucrose, or trehalose increases the binding affinity of glucose to the enzyme and increases fluorescence intensity. The effect of these osmolytes is thought to shift the protein conformation to a condensed, high affinity form. Based upon these results, we consider the nature of quenching of the Trp excited state. Amide groups are known to quench indole fluorescence and amides of the polypeptide chain make interact with excited state Trp in the relatively unstructured, glucose-free enzyme. Also, removal of water around the aromatic ring by addition of glucose substrate or osmolyte may reduce the quenching.

AB - Five variants of glucokinase (ATP-D-hexose-6-phosphotransferase, EC 2.7.1.1) including wild type and single Trp mutants with the Trp residue at positions 65, 99, 167 and 257 were prepared. The fluorescence of Trp in all locations studied showed intensity changes when glucose bound, indicating that conformational change occurs globally over the entire protein. While the fluorescence quantum yield changes upon glucose binding, the enzyme’s absorption spectra, emission spectra and fluorescence lifetimes change very little. These results are consistent with the existence of a dark complex for excited state Trp. Addition of glycerol, L-glucose, sucrose, or trehalose increases the binding affinity of glucose to the enzyme and increases fluorescence intensity. The effect of these osmolytes is thought to shift the protein conformation to a condensed, high affinity form. Based upon these results, we consider the nature of quenching of the Trp excited state. Amide groups are known to quench indole fluorescence and amides of the polypeptide chain make interact with excited state Trp in the relatively unstructured, glucose-free enzyme. Also, removal of water around the aromatic ring by addition of glucose substrate or osmolyte may reduce the quenching.

KW - Aromatic groups

KW - Dark complexes

KW - Glucokinase

KW - Glucose

KW - Glycerol

KW - Osmolites

KW - Tryptophan fluorescence

UR - http://www.scopus.com/inward/record.url?scp=85018810098&partnerID=8YFLogxK

U2 - 10.1007/s10895-017-2099-x

DO - 10.1007/s10895-017-2099-x

M3 - Article

VL - 27

SP - 1621

EP - 1631

JO - Journal of Fluorescence

JF - Journal of Fluorescence

SN - 1053-0509

IS - 5

ER -