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Research article - Peer-reviewed, 2014

CO2 and O-2 Distribution in Rubisco Suggests the Small Subunit Functions as a CO2 Reservoir

Van Lun, Michiel; Hub, Jochen S.; van der Spoel, David; Andersson, Inger

Abstract

Protein gas interactions are important in biology. The enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes two competing reactions involving CO2 and O-2 as substrates. Carboxylation of the common substrate ribulose-1,5-bisphosphate leads to photosynthetic carbon assimilation, while the oxygenation reaction competes with carboxylation and reduces photosynthetic productivity. The migration of the two gases in and around Rubisco was investigated using molecular dynamics simulations. The results indicate that at equal concentrations of the gases, Rubisco binds CO2 stronger than it does O-2. Amino acids with small hydrophobic side chains are the most proficient in attracting CO2, indicating a significant contribution of the hydrophobic effect in the interaction. On average, residues in the small subunit bind approximately twice as much CO2 as do residues in the large subunit. We did not detect any cavities that would provide a route to the active site for the gases. Instead, CO2 appears to be guided toward the active site through a CO2 binding region around the active site opening that extends to the closest neighboring small subunits. Taken together, these results suggest the small subunit may function as a "reservoir" for CO2 storage.

Published in

Journal of the American Chemical Society
2014, volume: 136, number: 8, pages: 3165-3171
Publisher: AMER CHEMICAL SOC

Authors' information

Van Lun, Michiel
Swedish University of Agricultural Sciences, Department of Molecular Biology
Hub, Jochen S.
University of Göttingen
van der Spoel, David
Uppsala University
Andersson, Inger
Uppsala University

UKÄ Subject classification

Biochemistry and Molecular Biology

Publication Identifiers

DOI: https://doi.org/10.1021/ja411579b

URI (permanent link to this page)

https://res.slu.se/id/publ/67662