Thermostability, hyperthermophilic enzyme

Vieille, C. and Zeikus, G.J. (2001) Hyperthermophilic enzymes sources, uses, and molecular mechanisms for thermostability. Microbiology and Molecular Biology Reviews, 65 (1), 1 43. 

A number of smaller enzyme-producing companies focus on thermophilic micro-organisms (and other extremophiles) to identify and produce new types of thermostable enzymes Unitika, Pacific Enzymes, Genis, Diversa (formerly Recombinant BioCatalysis), and others. One extremozyme that has already found commercial application is the heat-stable DNA polymerase from Thermus aquaticus (Taq-polymerase) that gave rise to the polymerase chain reaction (PCR). Using PCR, nucleic acids or segments of DNA can by amplified in vitro without having to replace the enzyme after each amplification cycle when the DNA template is denatured by heat. A number of new hyperthermophilic enzymes with temperature optima between 75 and 118°C have been described in the past few years [81], such as... 

Bock, A.K. Glasemacher, J. Schmidt, R. Schoenheit, P. Purification and characterization of two extremely thermostable enzymes, phosphate acetyltransferase and acetate kinase, from the hyperthermophilic eubacterium Thermotoga maritima. J. BacterioL, 181, 1861-1867 (1999)... 

Ramon-Maiques, S. Marina, A. Uriarte, M. Fita, L Rubio, V. The 1.5 A resolution crystal structure of the carbamate kinase-like carbamoyl phosphate synthetase from the hyperthermophilic Archaeon pyrococcus furio-sus, bound to ADP, confirms that this thermostable enzyme is a carbamate kinase, and provides insight into substrate binding and stability in carbamate kinases. J. Mol. Biol., 299, 463-476 (2000)... 

Temperature and pressure extremes require different strategies. Cellular lipids, proteins and nucleic acids are sensitive to high temperatures. Hyperthermophile bacteria have ether lipids instead of the more hydrolysis sensitive ester lipids in mesophiles [13]. Enzymes from hyperthermophiles show an unusual thermostability in the laboratory, and an important aspect of protein chemistry research is to find out the stabilizing principles. Crude cell extracts of hyperthermophiles show the presence of heat inducible proteins, called chaperones, which assist in the folding of proteins during cellular synthesis. Molecular details for cold adaptation of enzymes have been reported but are less extensively studied [14]. 

K. Goyal, P. Selvakumar, and K. Hayashi. 2001. Molecnlar cloning, purification and characterization of thermostable P-glucosidase from hyperthermophilic strain Thermotoga maritima activity in the presence of alcohols. J. Mol. Catal. B-Enzym. 15 45-53. 

Thermostable chaperonins are potentially useful for industrial application. In this article, methods to study archaeal chaperonins are discussed, which use as model systems recombinant forms of CpkA and CpkB from the hyperthermophilic archaeon Thermococcus kodakaraensis KODl, previously reported as Pyrococcus kodakaraensis KOD1. The enhancing effect of chaperonin on enzyme stability... 

In Volumes 330,331, and 334 of Methods in Enzymology, a set of protocols has been assembled that for the first time describe the methods involved in studying the biochemistry and biophysics of enzymes and proteins from hyperthermophilic microorganisms. As is evident from the various chapters, hyperthermophilic coun-terpatts to a range of previously studied but less thermostable enzymes exist. In addition, the volumes include descriptions of many novel enzymes that were first... 

The production and applications of thermostable enzymes by the culture of hyperthermophilic Archeae, especially those living in the vicinity of submarine hydro-thermal vents, was the subject of a recent review with an extensive bibliography (Huber and Stetter, 1998). 

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