Some Clues about Enzymes from Psychrophilic Microorganisms

Abstract

Enzymes purified from psychrophilic microorganisms prove to be efficient catalysts at low temperatures and possess a great potential for biotechnological applications. The low-temperature catalytic activity has to come from specific structural fluctuations involving the active site region, however, the relationship between protein conformational stability and enzymatic activity is subtle. We provide a survey of the thermodynamic stability of globular proteins and their rationalization grounded in a theoretical approach devised by one of us. Furthermore, we provide a link between marginal conformational stability and protein flexibility grounded in the harmonic approximation of the vibrational degrees of freedom, emphasizing the occurrence of long-wavelength and excited vibrations in all globular proteins. Finally, we offer a close view of three enzymes: chloride-dependent α-amylase, citrate synthase, and β-galactosidase.

Cold adapted Pseudomonas: ecology to biotechnology

“…Psychrophilic enzymes (phospholipases, proteases) maximise low temperature activity by destabilizing the structures containing the active site as well as the whole molecule. This attributes to a decrease in the strength of intramolecular connections (subunit, electrostatic interactions, disulfide linkages) ( Rapuano and Graziano, 2022 ) and the exclusion of stability factors, resulting in better active site dynamics ( Feller, 2013 ). Other factors responsible for the flexibility of such enzymes include enhanced surface, core hydrophobicity and the arrangement of aminoacids.…”

Psychrophilic enzymes: strategies for cold-adaptation

“…molecular dynamics simulations approaches, results in many cases point to an increased protein flexibility with decrease in physiological temperature. In particular, molecular dynamics simulations have become popular as they allow for more detailed definitions of flexibility [48] and the types of movements, atomic fluctuations, and vibrations involved [14], while also enabling for analysis of localized regions [49][50][51] and descriptions of catalytic reaction pathways [41,[52][53][54]. Moreover, and in agreement with an apparently localized heat lability at the active site as discussed above, the active site, associated surface loops, and other regions involved in enzyme function, have also been reported to be the most flexible structural elements of the molecular edifice of many cold-adapted enzymes [41,50].…”

“…They have adapted their cellular components and processes to overcome the barriers inherent to their extreme environment: from adaptation of their enzymatic repertoire and cell envelop; to the production of chaperones and cryoprotectants such as antifreeze and ice-nucleating compounds; and even metabolic adjustments [12]. Of these adaptations, enzymes, which drive microbial metabolism and the cell cycle, have been the most intensely studied [13,14], and their adaptation is seen as being a key component to life in the cold. The present paper, based on updates of previous publications [15][16][17][18][19][20][21], will focus on enzymes produced by psychrophiles, presenting the general features of these while also discussing their less common characteristics and delineating their adaptation strategies.…”