Extremophilic Proteases: Developments of Their Special Functions, Potential Resources and Biotechnological Applications

[L-asparaginases of extremophilic microorganisms in biomedicine]

L-asparaginase is extensively used in the treatment of acute lymphoblastic leukemia and several other lymphoproliferative diseases. In addition to its biomedical application, L-asparaginase is also of prospective use in food industry to reduce the formation of acrylamide, which is classified as probably neurotoxic and carcinogenic to human, and in biosensors for determination of L-asparagine level in medicine and food chemistry. The importance of L-asparaginases in different fields, disadvantages of commercial ferments, and the fact that they are widespread in nature stimuli the search for biobetter L-asparaginases from new producing microorganisms. In this regard, extremofile microorganisms exhibit unique physiological properties such as thermal stability, adaptability to extreme cold conditions, salt and pH tolerance and so provide one of the most valuable sources for novel L-asparaginases. The present review summarizes the recent results on studying the structural, functional, physicochemical and kinetic properties, stability of extremophilic L-asparaginases in comparison with their mesophilic homologues.

Extremophilic proteases as novel and efficient tools in short peptide synthesis

The objective of this review is to outline the crucial role that peptides play in various sectors, including medicine. Different ways of producing these compounds are discussed with an emphasis on the benefits offered by industrial enzyme biotechnology. This paper describes mechanisms of peptide bond formation using a range of proteases with different active site structures. Importantly, these enzymes may be further improved chemically and/or genetically to make them better suited for their various applications and process conditions. The focus is on extremophilic proteases, whose potential does not seem to have been fully appreciated to date. The structure of these proteins is somewhat different from that of the common commercially available enzymes, making them effective at high salinity and high or low temperatures, which are often favorable to peptide synthesis. Examples of such enzymes include halophilic, thermophilic, and psychrophilic proteases; this paper also mentions some promising catalytic proteins which require further study in this respect.

Draft genome sequence of Thermoactinomyces sp. strain AS95 isolated from a Sebkha in Thamelaht, Algeria

The members of the genus Thermoactinomyces are known for their protein degradative capacities. Thermoactinomyces sp. strain AS95 is a Gram-positive filamentous bacterium, isolated from moderately saline water in the Thamelaht region of Algeria. This isolate is a thermophilic aerobic bacterium with the capacity to produce extracellular proteolytic enzymes. This strain exhibits up to 99 % similarity with members of the genus Thermoactinomyces, based on 16S rRNA gene sequence similarity. Here we report on the phenotypic features of Thermoactinomyces sp. strain AS95 together with the draft genome sequence and its annotation. The genome of this strain is 2,558,690 bp in length (one chromosome, but no plasmid) with an average G + C content of 47.95 %, and contains 2550 protein-coding and 60 RNA genes together with 64 ORFs annotated as proteases.