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Sagoo K, Hirsch R, Johnston P, McLoskey D, Hungerford G. Pre-denaturing transitions in human serum albumin probed using time-resolved phosphorescence. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 124:611-617. [PMID: 24509539 DOI: 10.1016/j.saa.2014.01.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/07/2014] [Accepted: 01/10/2014] [Indexed: 06/03/2023]
Abstract
The investigation of protein dynamics has long been of interest, since protein interactions and functions can be determined by their structure and changes in conformation. Although fluorescence, occurring on the nanosecond timescale, from intrinsic fluorescent amino acids has been extensively used, in order to fully access conformational changes longer timescales are required. Phosphorescence enables processes on the microsecond to second timescale to be accessed. However, at room temperature this emission can be weak and non trivial to measure. It requires the removal of oxygen - a common triplet state quencher and appropriate instrumentation. In this work we make use of a chemical deoxygenator to study room temperature phosphorescence from tryptophan in human serum albumin excited using a pulsed UV light emitting diode. This is extended to monitor the phosphorescence emission upon increasing temperature, allowing pre-denaturing transitions to be observed. Time-resolved data are analysed, both as the sum of exponential decays and using a distribution analysis based on non extensive decay kinetics. These results are compared to a fluorescence study and both the average lifetime and contribution of the different emitting components were found to give more dramatic changes on the phosphorescence timescale.
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Affiliation(s)
- Kulwinder Sagoo
- HORIBA Jobin Yvon IBH Ltd., 45 Finnieston Street, Glasgow G3 8JU, UK
| | - Richard Hirsch
- HORIBA Jobin Yvon IBH Ltd., 45 Finnieston Street, Glasgow G3 8JU, UK
| | - Pamela Johnston
- HORIBA Jobin Yvon IBH Ltd., 45 Finnieston Street, Glasgow G3 8JU, UK
| | - David McLoskey
- HORIBA Jobin Yvon IBH Ltd., 45 Finnieston Street, Glasgow G3 8JU, UK
| | - Graham Hungerford
- HORIBA Jobin Yvon IBH Ltd., 45 Finnieston Street, Glasgow G3 8JU, UK.
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Harriman A, Mallon LJ, Elliot KJ, Haefele A, Ulrich G, Ziessel R. Length Dependence for Intramolecular Energy Transfer in Three- and Four-Color Donor−Spacer−Acceptor Arrays. J Am Chem Soc 2009; 131:13375-86. [DOI: 10.1021/ja9038856] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Anthony Harriman
- Molecular Photonics Laboratory, School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom, and Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
| | - Laura J. Mallon
- Molecular Photonics Laboratory, School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom, and Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
| | - Kristopher J. Elliot
- Molecular Photonics Laboratory, School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom, and Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
| | - Alexandre Haefele
- Molecular Photonics Laboratory, School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom, and Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
| | - Gilles Ulrich
- Molecular Photonics Laboratory, School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom, and Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
| | - Raymond Ziessel
- Molecular Photonics Laboratory, School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom, and Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
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Rolinski OJ, Scobie K, Birch DJS. Protein fluorescence decay: a gamma function description of thermally induced interconversion of amino acid rotamers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:050901. [PMID: 19518409 DOI: 10.1103/physreve.79.050901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Indexed: 05/27/2023]
Abstract
We present a description of fluorescence decay kinetics in complex environments based on gamma functions rather than the conventional approach using exponentials. The gamma function description is tested in measurements on the temperature dependence of the protein human serum albumin (HSA), N-acetyl tryptophanamide (NATA), and 2, 5-dipenyl oxazole (PPO). The monitoring of macromolecular structure and dynamics is demonstrated by means of distinct tryptophan (Trp) rotamer populations and their interconversion in HSA.
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Affiliation(s)
- Olaf J Rolinski
- Department of Physics, Scottish Universities Physics Alliance, Photophysics Group, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG, United Kingdom
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