Comparative structural analysis of psychrophilic and meso- and thermophilic enzymes.
Enzymes adapted to cold display structures comparable with those of their meso- and thermophilic homologs but are characterized by a higher catalytic efficiency at low temperatures and by thermolability at moderate temperatures. To identify the structural factors responsible of such features, we undertook a systematic comparative analysis of several structural properties in a data set consisting of 7 cold active enzymes belonging to different structural families and 28 related structures from meso/thermophiles representing most of the structural information now available. Only high-resolution and high-quality structures were considered. Properties were calculated and then compared for each pair of 3D structures displaying different temperatures of adaptation using a temperature-weighting scheme. The significance of the resulting differences was evaluated with a statistical method. Results reveal that each protein family adopts different structural strategies to adapt to low temperatures. However, some common trends are observed: the number of ion pairs, the side-chain contribution to the exposed surface, and the apolar fraction of the buried surface show a consistent decrease with decreasing optimal temperatures.
Gianese
Giulio
G
Dipartimento di Scienze Biochimiche, A. Rossi Fanelli, and Centro di Biologia Molecolare del C.N.R., Università La Sapienza, Roma, Italy.
Bossa
Francesco
F
Pascarella
Stefano
S
D000222:Adaptation, Physiological; D000818:Animals; D003080:Cold Temperature; D004798:Enzymes / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D055672:Static Electricity; D014867:Water / Q000737:chemistry
D004798:Enzymes; D014867:Water