THERMOPHOLE
Thermophiles: Adapted to high temperatures e.g. thermal vents and hot springs. EXAMPLE: Obsidian
pool in Yellowstone national park which is ~150-350C
phsychrophile
Adapted to low temperatures e.g. arctic and Antarctic. Half of the Earth’s surface is
oceans between 1-4ᵒC. Temperatures in Antarctic are more stable than artic (-10 to -30)
Protein structure regulation
Stable proteins for thermophiles but psychrophiles have efficient proteins
Adaptations of hyperthermophiles 1
HYDROPHOBICITY
- heat stable proteins have more hydrophobic interiors
-prevents unfolding or denaturing - Thermophilic proteins are kept stable, so more energy is needed to cause protein conformation
- Avoid Cys and Thr residues and prefer Arg and Tyr
o They do NOT favour proline and where there are breaks between a and B helices
o Prefer carbon and sulfur bonds as hydrogen bonds are more unstable
o Prefer more a helices (but both are needed in proteins)
adaption of hyperthermophiles
ABUNDANT CHAPERONE PROTEINS
- MAINTAIN FOLDING
- 10% OF GENES IN GENOMES ARE CHAPERONES
A O H,
MONOLAYER MEMBERANES OF DIBPHYTANYL TETRAETHERS
- SATURATED acids that make them RIGID
- prevents membrane DEGRADATION
- increased cyclisation, so packaged TIGHT and LESS LIPID MOVEMENT
- 10-20X THICKER than normal
- some species have INCREASED MOTION which increasesPROTON PERMEABILITY (IMPORTANT TO ENZYMEATIC ABILIUTY)
dna preserving substrates
Reduces mutations and damage
o E.g. DNA gyrase and Sac7d
o Large mutation rate to maintain integrity
o Lots of positive changes but needs lots of active repair mechanisms e.g. DNA pol helices
Surviving on sulphur, hydrogen and other materials that other organisms can’t metabolise
- live without sunlight or organic carbon source
- save metabolic activity through using sodium/proton transport exchange
- converts PMF (proton motive force) into SMF (sodium motive force)
o High PMF generated by high respiration rate
o Saved energy used for other processes e.g. secondary transport
o Lots of TM proteins
o H+ and sodium used to produce ATP
o EXAMPLE: Thermophilic cyanobacteria in geysers
extremosymes
enzyme from extremophile
EXAMPLE: P. abyssi and T. aquaticus
- Hydrothermal vents: high temperatures, low nutrient levels (mostly only oligotrophs, survive at low nutrient level) and high pressures (increase rate of 1atm for every 10 meters in depth in deep sea)
- Increased pressure = decreased enzyme-substrate binding
EXAMPLE: Thermus thermophilus
o Small circular genome (2Mbp), 2000 predicted genes
o Large plasmid >200 kbp
o shows features of a scavenger (lots of peptidases involved in protein folding or stability)
o Lots of overlap between genomes T. thermophilus and D. radiodurans (horizontal gene transfer?)
o Lots of NTN codons (nucleotide – thymine – nucleotide), T instead of U
o NTN encodes exclusively non-polar hydrophobic amino acids (for stabilisation)
o Mutated rapidly to preference specific codon = atypical residues = stability
o Traps and protects H bonds from moving
Barotolerent
: microbes live at 1000-4000 meters
Barophilic
microbes live at >4000 meters
1) Bacteriophages
o Cannot culture in lab very well as need lots of components
o Electron dense structures
o Lack some metabolic processes, shows did not evolve alone and live in communities
3) Archaeal viruses
o Large circular double-stranded DNA genome ~20,000 bp (not common to bacterial viruses)
o No similarity to any other known genome
o Capsid proteins found similar with bacteria and viruses
