A Microbial Biorealm page on the genus Staphylothermus marinus
Higher order taxa
Archaea; Crenarchaeota; Thermoprotei; Desulfurococcales; Desulfurococcaceae; Staphylothermus
Description and significance
Staphylothermus marinus is a hyperthermophilic, marine organism that was isolated from naturally heated sediment on the beach of Vulcano Island, Italy in 1986. It can also be found from "black smokers" on the ocean floor. In a rich medium, Staphylothermus marinus grows in an optimum temperature of 92 degrees Celsius, but when nutrients are sparce, the optimum temperature drops to 85 degrees Celsius. For growth in a lab, a complex nutrient source is needed for optimum growth. (1)
The morphology of the Staphylothermus marinus can differ depending on the nutrients available. When nutrients are plentiful, Staphylothermus marinus grows as giant cells in a slightly irregular coccus shape with diameters up to 15 mm. Low nutrient concentrations produce little cells with diameters ranging from 0.5 to 1.0 mm. Up to 100 of these cells can cluster together to form grape-like groups.
S. marinus is related to Aeropyrum pernix, Hyperthermus butylicus, and Ignicoccus hospitalis. (5)
The current genome of S. marinus is a circular 1.57 million base pairs long. The GC content is 35.7% with a gene count of 1646. There are 45 RNAs found in the organism.(5)
Cell structure and metabolism
The cell wall of Staphylothermus marinus is composed of an unusual stucture called tetrabrachion. It is a glycoprotein complex that is very stable at high temperatures which is even resistant to chemicals that denature proteins. Tetrabrachion is composed of a stalk that's connected to the membrane on one end and has four arms protruding perpendicularly from the other end. These four arms interact with other tetrabrachion groups to form a latticework that covers the cell. (2)
S. marinus is heterotrophic and requires elemental sulfur as a nutrient for growth. The sulfur is then reduced to hydrodren sulfide as a waste product. (3)
Staphylothermus marinus was isolated from heated, ocean sediment from Vulcano Island in Italy and also from a marine, hydrothermal vent at the East Pacific Rise. Due to the extreme heat, no organisms were thought to have lived there. Staphylothermus marinus is now sequenced to be compared with other Archaea hyperthermophiles. (1)
Application to Biotechnology
S. marinus has amylase, which is an enzyme that catalyzes the hydrolysis of starch. There is a possibility of researching the amylase in S. marinus to evaluate its usefulness in starch processing. The enzyme can be used to produce glucose from liquefied starch. Many thermophiles are being researched in this way. (8)
1. One of the major steps in protein folding is getting rid of water from the protein core. In S. marinus, large water clusters, 7 to 9 water molecules, have been found in the nonpolar cavities of the tetrabrachion. At about 110 degrees Celsius, the clustering becomes unfavorable and signals the drying process to begin. This drying process is the start of protein denaturation. The study shows that the unusually stable tetrabrachion structure can possibly be explained by the large hydrophobic cavities that are the binding sites for two proteases. (4)
2. One of the proteases in S. marinus has been tested to be one of the most stable proteases known to man. It is part of the subtilisin family and is the only known ezyme that is part of the S-layer. It has a very high resistance toward denaturing agents. (7)
3. The phosphoenolpyruvate synthase of S. marinus has been an interest to academia due to its unusual stability in high temperatures. The synthase forms a homomultimeric complex which is 83 kDa subunits large, and analysis has shown a core with a threefold rotational symmetry. It is suggested that the unique structure of the enzyme is an adaptation to the organism's extreme environment. (6)
(1) Fiala, G; Stetter, KO; Jannasch, HW; Langworthy, TA; Madon, J. Staphylothermus marinus sp.nov. represents a novel genus of extremely thermophilic submarine heterotrophic archaebacteria growing up to 98 degree C. Systematic and Applied Microbiology [SYST. APPL. MICROBIOL.]. Vol. 8, no. 1-2, pp. 106-113. 1986.
(2) Peters J., Nitsch M., Kuhlmorgen B., Golbik R., Lupas A., Kellermann J., Engelhardt H., Baumeister W. Tetrabrachion: A filamentous archaebacterial surface protein assembly of unusual structure and extreme stability (1995) Journal of Molecular Biology, 245 (4), pp. 385-401.
(3) Hao, Xiaolei. (2003). Minimal sulfur requirement for growth and sulfur-dependent metabolism of the hyperthermophilic archaeon Staphylothermus marinus. Archaea, 1(3), 191-197.
(4) Yin, H. (2007). Metastable water clusters in the nonpolar cavities of the thermostable protein tetrabrachion. Journal of the American Chemical Society, 129(23), 7369-7377.
(5) The UCSC Archaeal Genome Browser Kevin L. Schneider , Katherine S. Pollard , Robert Baertsch , Andy Pohl , and Todd M. Lowe The UCSC Archaeal Genome Browser. Nucl. Acids Res. 34: D407-D410.
(6) Harauz et al 1996. G. Harauz, C. Cicicopol, R. Hegerl, Z. Cejka, K. Goldie, U. Santarius, A. Engel and W. Baumeister, Structural studies on the 2.25 MDa homomultimeric Phosphoenolpyruvate Synthase from Staphylothermus marinus. J. Struct. Biol. 116 (1996), pp. 290–301.
(7) Mayr J., Lupas A., Kellermann J., Eckerskorn C., Baumeister W., Peters J. A hyperthermostable protease of the subtilisin family bound to the surface layer of the Archaeon Staphylothermus marinus (1996) Current Biology, 6 (6), pp. 739-749.
(8)Carolina M.M.C. Andrade1; Nei Pereira Jr.; Garo Antranikian. Extremely thermophilic microorganisms and their polymerhidrolytic enzymes. (1999) Rev. Microbiol. v.30 n.4 São Paulo oct./dic. 1999.
Edited by Julie Liu student of Rachel Larsen
Edited by KLB