Natural fiber Keratin is a structural protein located at the hard surfaces in many vertebrates. Keratin has two forms, α-keratin and β-keratin and are used by different classes of animals. The naming convention for proteins follows that for keratin, alpha keratin is helical and beta keratin is sheet like. Alpha keratin is found in mammalian hair, skin, nails, horn and quills, while beta keratin can be found in avian and reptilian species in scales, feathers, and beaks. The two different structures of keratin have dissimilar mechanical properties, as seen in their dissimilar applications. The relative alignment of the keratin fibrils has a
Ribosomal protein leader form an intrinsic transcription termination stem-loop. When cellular concentrations of the ribosomal protein are not high, they are occupied in the ribosome, and are not available in significant quantities to bind the mRNA leader. This leads to increased expression of the gene, which leads to the synthesis of more copies of the ribosomal protein. Many examples of ribosomal protein leaders are known in bacteria, including ribosomal protein L20 leader and ribosomal S15 leader. Ribosomal protein leader A ribosomal protein leader is a mechanism used in cells to control the cellular concentration of a protein that forms a part of the