Passage:
In abyssal benthic ecosystems, hydrothermal vent archaea rely on chemolithoautotrophy, oxidizing reduced sulfur compounds to fix inorganic carbon in total darkness. Recent biochemical studies of Pyrococcus isolates from the Mid-Atlantic Ridge demonstrate that these microorganisms express modified hydrogenase enzymes whose catalytic efficiency peaks only at hydrostatic pressures exceeding 30 megapascals (MPa). When cultured at atmospheric pressure (0.1 MPa) while maintaining identical temperature and nutrient concentrations, the enzymatic turnover rate drops by over 90 percent due to structural destabilization of the enzyme's active site. Furthermore, while surface-dwelling sulfur-oxidizing bacteria utilize heat-shock proteins to maintain enzyme integrity during thermal spikes, Pyrococcus isolates lack the genes encoding these specific heat-shock chaperones, relying instead on pressure-induced conformational rigidity to prevent thermal denaturation.
Statement: Based on the passage, Pyrococcus enzymes are more vulnerable to thermal denaturation when exposed to thermal spikes at atmospheric pressure than when exposed to the same thermal spikes under high hydrostatic pressure.
Cevap: Cevap