Storage protein 3-Strand

A biochemical curiosity is the presence in egg white of the glycoprotein avidin.ab Each 68-kDa subunit of this tetrameric protein binds one molecule of biotin tenaciously with Kf 1015 M 1. Nature s purpose in placing this unusual protein in egg white is uncertain. Perhaps it is a storage form of biotin, but it is more likely an antibiotic that depletes the environment of biotin. A closely similar protein streptavidin is secreted into the culture medium by Streptomyces avidinii.c Its sequence is homologous to that of avidin. It has a similar binding constant for biotin and the two proteins have similar three-dimensional structures.3/d i Biotin binds at one end of a P barrel formed from antiparallel strands and is held by multiple hydrogen bonds and a conformational alteration that allows a peptide loop to close over the bound vitamin. 

Deoxyribonucleic acid (DNA) a huge nucleotide polymer having a double-helical structure with complementary bases on the two strands. Its major functions are protein synthesis and the storage and transport of genetic information. (22.6) Desalination the removal of dissolved salts from an aqueous solution. (17.6)... 

The fungal cell contains a vast number of ribosomes, which are usually present in the form of polysomes — lines of ribosomes strung together by a strand of mRNA. Ribosomes are the site of protein biosynthesis. The system that mediates the export of proteins from the cell involves a number of membranous compartments including the Golgi apparatus, the endoplasmic reticulum and the plasmalemma. In addition, the vacuole is employed as a storage space where nutrients, hydrolytic enzymes... 

A huge nucleotide polymer having a doublehelical structure with complementary bases on the two strands functions include protein synthesis and the storage and transport of genetic material... 

In the cell, nucleic acids are involved in the storage of genomic information and the production of proteins. However, other functions of nucleic acids, especially RNA, have been discovered. For example, ribosomal RNAs not only fold the structure of the ribosome but play an important role in protein synthesis (Moore and Steitz, 2002), and the RNA-induced silencing complex (RICS) is composed of a guide strand of siRNA or microRNA and proteins to control gene expression through RNA interference (Filipowicz, 2005). Those RNAs and proteins work cooperatively to achieve complicated tasks. This means that if we could engineer a nucleic acid-protein complex, we could construct more functional biosensor systems. 

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