Replicons have genes for: DNA polymerase Transcription factors 3 chromosomes Main chromosome 2,015 kb 191 kb replicon 366 kb replicon Replicons have genes for: DNA polymerase Transcription factors Mineral uptake (K, PO4) Cell division The genome has many insertion sites for foreign genes Bacteriorhodopsin: Protein + retinal Amax 280 UV, 570 green nm energy for proton transport and phosphorylation without photosynthesis! Halobacterium salinarum http://biology.kenyon.edu/Microbial_Biorealm/ archaea/halobacterium/halobacteria_1.jpg Aerobic Respiration Up to 5 M (25% NaCl)! Great Salt Lake, Utah Red Sea, Asia Minor

Hint: it reflects the other colors of the spectrum Periplasmic space Cell Membrane Retinal lsu.epfl.ch/sh/bR_full.pdf Bacteriorhodopsin absorbs green from the visible spectrum, so what color is the pigment? Cytoplasm Hint: it reflects the other colors of the spectrum www.hawaii.edu/microbiology/ Alam/publications/PNAS96-ZHANG.pd

How do Archaea tolerate the heat? Proteins stabilized by more ionic bridges between amino acid r-groups and more-hydrophobic core amino acids Heat shock protein (chaperonins) refold denatured proteins…Pyrococcus 121°C for 1 hour! DNA depurination reduced by presence of 2,3-diphosphoglycerate. DNA supercoiling by reverse gyrase reduces denaturation Sac7d in Sulfolobus is a minor groove protein increases the melting temperature by 40°C Histone-like proteins help stabilize DNA as well Heat-resistant di-bi-phytanyl diether lipid membranes (monolayer) prevent delamination of membrane

Cell Membrane Structure Composed of diglycerides R group may be phosphate, sulfate, or sugar Long chain branched hydrocarbon (not fatty acid) Hydrocarbons may be C20 or C40 If C20, the membrane is a bilayer: O R If C40, the membrane is a monolayer O R In some species, the membrane is a mixture of both C20 and C40 diglycerides forming a mixed mono-/bi-layer. The C40 diglycerides prevent the bi-layer from de-laminating!

Thermus aquaticus Gram negative eubacterium Thermophile isolated from Not all thermophiles are archaeons Thermus aquaticus Gram negative eubacterium Thermophile isolated from Yellowstone Hot Spring Optimum temperature 85°C Stability of macromolecules excellent Enzymes for research or commercial use--Taq polymerase is the enzyme of PCR (Polymerase Chain Reaction) Lives near cyanobacteria which feed CH2O to Thermus http://www.molgen.mpg.de/~ag_ribo/ ag_franceschi/franceschi-projects-30S.html http://sci.agr.ca/crda/images/BACTERI1.JPG