Kinetic nature of the thermal destabilization of LHCII macroaggregates

Sashka B Krumova; Svetla J Todinova; Mira C Busheva; Stefka G Taneva

doi:10.1016/j.jphotobiol.2004.11.005

Kinetic nature of the thermal destabilization of LHCII macroaggregates

J Photochem Photobiol B. 2005 Feb 1;78(2):165-70. doi: 10.1016/j.jphotobiol.2004.11.005.

Authors

Sashka B Krumova¹, Svetla J Todinova, Mira C Busheva, Stefka G Taneva

Affiliation

¹ Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 21, 1113 Sofia, Bulgaria.

PMID: 15664504
DOI: 10.1016/j.jphotobiol.2004.11.005

Abstract

The main light-harvesting chl a/b pigment-protein complex of photosystem II (LHCII) in isolated state forms macroaggregates with different ultrastructure and lipid content [I. Simidjiev, V. Barzda, L. Mustardy, G. Garab, Anal. Biochem. 250 (1997) 169-175]. The thermodynamic stability of highly delipidated tightly bound LHCII macroaggregates is studied by differential scanning calorimetry and fluorescence spectroscopy. The calorimetric profile of LHCII is asymmetric, the denaturation transition is taking place at around 72 degrees C. A shoulder, which overlaps with the main denaturation transition, appears around 58 degrees C. The denaturation temperature strongly depends on the scanning rate indicating the kinetic nature of the thermal destabilization of LHCII macroaggregates. The fluorescence data prove that the thermal denaturation of LHCII is an irreversible and kinetically controlled process.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Calorimetry, Differential Scanning
Enzyme Stability
Kinetics
Photosystem II Protein Complex / chemistry*
Photosystem II Protein Complex / isolation & purification
Photosystem II Protein Complex / metabolism*
Pisum sativum / enzymology
Protein Denaturation
Spectrometry, Fluorescence
Spinacia oleracea / enzymology
Temperature

Substances

Photosystem II Protein Complex