Archaea living in extreme environments have evolved specific protein adaptations to survive. Thermophilic proteins have a hydrophobic core and more electrostatic interactions for high temperatures. Psychrophilic proteins have less hydrophobic core and fewer charges for cold temperatures. Halophilic proteins have more negative charges to handle extreme salt conditions. Acidophiles, alkaliphiles, and piezophiles also have unique adaptations. Understanding these protein adaptations can help in creating useful proteins for industries and biotechnology in extreme conditions.