Evidence of energy transfer from tryptophan to BSA/HSA protected gold nanoclusters

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Abstract

This work reports on the chromophores interactions within protein-protected gold nanoclusters. We conducted spectroscopic studies of fluorescence emissions originated from gold nanoclusters and intrinsic tryptophan (Trp) in BSA or HSA proteins. Both steady state fluorescence and lifetime measurements showed a significant Forster Resonance Energy Transfer (FRET) from Trp to the gold nanocluster. Tryptophan lifetimes in the case of protein-protected gold nanoclusters are 2.6 ns and 2.3 ns for BSA and HSA Au clusters while 5.8 ns for native BSA and 5.6 for native HSA. The apparent distances from Trp to gold nanocluster emission center, we estimated as 24.75 Å for BSA and 23.80 Å for HSA. We also studied a potassium iodide (KI) quenching of protein-protected gold nanoclusters and compared with the quenching of BSA and HSA alone. The rates of Trp quenching were smaller in BSA-Au and HSA-Au nanoclusters than in the case of free proteins, which is consistent with shorter lifetime of quenched Trp(s) and lower accessibility for KI. While Trp residues were quenched by KI, the emissions originated from nanoclusters were practically unquenched. In summary, for BSA and HSA Au clusters, we found 55% and 59% energy transfer efficiency respectively from tryoptophan to gold clusters. We believe this interaction can be used to our advantage in terms of developing resonance energy transfer based sensing applications.

Original languageEnglish
Article number035004
JournalMethods and Applications in Fluorescence
Volume2
Issue number3
DOIs
StatePublished - 1 Sep 2014

Fingerprint

Nanoclusters
tryptophan
nanoclusters
Tryptophan
Gold
Energy transfer
energy transfer
gold
proteins
Proteins
Quenching
quenching
life (durability)
Fluorescence
Potassium iodide
potassium iodides
Potassium Iodide
fluorescence
Chromophores
chromophores

Keywords

  • BSA Au clusters
  • FRET
  • Gold clusters
  • HSA Au clusters
  • Tryptophan

Cite this

@article{945c8af150474be69d637445ba3618ed,
title = "Evidence of energy transfer from tryptophan to BSA/HSA protected gold nanoclusters",
abstract = "This work reports on the chromophores interactions within protein-protected gold nanoclusters. We conducted spectroscopic studies of fluorescence emissions originated from gold nanoclusters and intrinsic tryptophan (Trp) in BSA or HSA proteins. Both steady state fluorescence and lifetime measurements showed a significant Forster Resonance Energy Transfer (FRET) from Trp to the gold nanocluster. Tryptophan lifetimes in the case of protein-protected gold nanoclusters are 2.6 ns and 2.3 ns for BSA and HSA Au clusters while 5.8 ns for native BSA and 5.6 for native HSA. The apparent distances from Trp to gold nanocluster emission center, we estimated as 24.75 {\AA} for BSA and 23.80 {\AA} for HSA. We also studied a potassium iodide (KI) quenching of protein-protected gold nanoclusters and compared with the quenching of BSA and HSA alone. The rates of Trp quenching were smaller in BSA-Au and HSA-Au nanoclusters than in the case of free proteins, which is consistent with shorter lifetime of quenched Trp(s) and lower accessibility for KI. While Trp residues were quenched by KI, the emissions originated from nanoclusters were practically unquenched. In summary, for BSA and HSA Au clusters, we found 55{\%} and 59{\%} energy transfer efficiency respectively from tryoptophan to gold clusters. We believe this interaction can be used to our advantage in terms of developing resonance energy transfer based sensing applications.",
keywords = "BSA Au clusters, FRET, Gold clusters, HSA Au clusters, Tryptophan",
author = "Raut, {Sangram Limbaji} and Rahul Chib and Susan Butler and Julian Borejdo and Zygmunt Gryczynski and Ignacy Gryczynski",
year = "2014",
month = "9",
day = "1",
doi = "10.1088/2050-6120/2/3/035004",
language = "English",
volume = "2",
journal = "Methods and applications in fluorescence",
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Evidence of energy transfer from tryptophan to BSA/HSA protected gold nanoclusters. / Raut, Sangram Limbaji; Chib, Rahul; Butler, Susan; Borejdo, Julian; Gryczynski, Zygmunt; Gryczynski, Ignacy.

In: Methods and Applications in Fluorescence, Vol. 2, No. 3, 035004, 01.09.2014.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Evidence of energy transfer from tryptophan to BSA/HSA protected gold nanoclusters

AU - Raut, Sangram Limbaji

AU - Chib, Rahul

AU - Butler, Susan

AU - Borejdo, Julian

AU - Gryczynski, Zygmunt

AU - Gryczynski, Ignacy

PY - 2014/9/1

Y1 - 2014/9/1

N2 - This work reports on the chromophores interactions within protein-protected gold nanoclusters. We conducted spectroscopic studies of fluorescence emissions originated from gold nanoclusters and intrinsic tryptophan (Trp) in BSA or HSA proteins. Both steady state fluorescence and lifetime measurements showed a significant Forster Resonance Energy Transfer (FRET) from Trp to the gold nanocluster. Tryptophan lifetimes in the case of protein-protected gold nanoclusters are 2.6 ns and 2.3 ns for BSA and HSA Au clusters while 5.8 ns for native BSA and 5.6 for native HSA. The apparent distances from Trp to gold nanocluster emission center, we estimated as 24.75 Å for BSA and 23.80 Å for HSA. We also studied a potassium iodide (KI) quenching of protein-protected gold nanoclusters and compared with the quenching of BSA and HSA alone. The rates of Trp quenching were smaller in BSA-Au and HSA-Au nanoclusters than in the case of free proteins, which is consistent with shorter lifetime of quenched Trp(s) and lower accessibility for KI. While Trp residues were quenched by KI, the emissions originated from nanoclusters were practically unquenched. In summary, for BSA and HSA Au clusters, we found 55% and 59% energy transfer efficiency respectively from tryoptophan to gold clusters. We believe this interaction can be used to our advantage in terms of developing resonance energy transfer based sensing applications.

AB - This work reports on the chromophores interactions within protein-protected gold nanoclusters. We conducted spectroscopic studies of fluorescence emissions originated from gold nanoclusters and intrinsic tryptophan (Trp) in BSA or HSA proteins. Both steady state fluorescence and lifetime measurements showed a significant Forster Resonance Energy Transfer (FRET) from Trp to the gold nanocluster. Tryptophan lifetimes in the case of protein-protected gold nanoclusters are 2.6 ns and 2.3 ns for BSA and HSA Au clusters while 5.8 ns for native BSA and 5.6 for native HSA. The apparent distances from Trp to gold nanocluster emission center, we estimated as 24.75 Å for BSA and 23.80 Å for HSA. We also studied a potassium iodide (KI) quenching of protein-protected gold nanoclusters and compared with the quenching of BSA and HSA alone. The rates of Trp quenching were smaller in BSA-Au and HSA-Au nanoclusters than in the case of free proteins, which is consistent with shorter lifetime of quenched Trp(s) and lower accessibility for KI. While Trp residues were quenched by KI, the emissions originated from nanoclusters were practically unquenched. In summary, for BSA and HSA Au clusters, we found 55% and 59% energy transfer efficiency respectively from tryoptophan to gold clusters. We believe this interaction can be used to our advantage in terms of developing resonance energy transfer based sensing applications.

KW - BSA Au clusters

KW - FRET

KW - Gold clusters

KW - HSA Au clusters

KW - Tryptophan

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DO - 10.1088/2050-6120/2/3/035004

M3 - Article

VL - 2

JO - Methods and applications in fluorescence

JF - Methods and applications in fluorescence

SN - 2050-6120

IS - 3

M1 - 035004

ER -