Re: How do hyperthermophiles tolerate extreme heat?

Thermophiles contain enzymes (proteins) and cellular adaptations that allow them to thrive in extremely hot conditions.

The enzymes seem to be the key to their survival. They function only at high temperatures. Thermophiles also have an increase in the G-C content of guanine (G) and cytidiine (C) nucleotide pairs in their DNA (1,2). While most DNA begins to unravel when water temperatures get near boiling, thermophilic DNA is more stable and won't unravel. The thermophile protein enzymes also hold their 3-D shapes together by folding themselves tighter than enzymes from organisms growing at normal temperature do (2). That way the high temps don't make them unravel. The enzymes are also more rigid due to the amino acid abundances (2).

Thermophiles also have thick membranes inside their cells, layers that are chemically glued together. Instead of a bilayer that could be pulled apart in intense heat like other organisms have, thermophiles have a thick single or monolayer (2).

To read about thermophiles in Yellowstone National Park, see the booklet in (3).

(1) High guanine plus cytosine content in the third letter of codons of an extreme thermophile.

(2) http://www.microbe.org/microbes/thermophiles.asp

(3)Life at High Temperatures