Protein biosynthesis
Protein biosynthesis (synthesis) is when cells build proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process.
Amino acids are either synthesised or eaten in food. Then, after the transcription of polypeptide genes, the amino acids are put together. This is done by translation and RNA splicing which produces messenger RNAs. The splicing process produces the final proteins, which then fold up into their protein structure. Then they can function. The plural is used here because, with most genes, the splicing process produces more than one final working protein. One particular Drosophila gene (DSCAM) can be alternatively spliced into 38,000 different mRNA.[1]
Protein biosynthesis differs between prokaryotes and eukaryotes, though parts of the process are the same in both.
Protein Biosynthesis Media
Protein biosynthesis starting with transcription and post-transcriptional modifications in the nucleus. Then the mature mRNA is exported to the cytoplasm where it is translated. The polypeptide chain then folds and is post-translationally modified.
Illustrates the conversion of the template strand of DNA to the pre-mRNA molecule by RNA polymerase.
Outlines the process of post-transcriptionally modifying pre-mRNA through capping, polyadenylation and splicing to produce a mature mRNA molecule ready for export from the nucleus.
Illustrates the translation process showing the cycle of tRNA codon-anti-codon pairing and amino acid incorporation into the growing polypeptide chain by the ribosome.
Shows the process of a polypeptide chain folding from its initial primary structure through to the quaternary structure.
Shows the post-translational modification of protein by methylation, acetylation and phosphorylation
Illustrates the difference in structure between N-linked and O-linked glycosylation on a polypeptide chain.
Shows the formation of disulphide covalent bonds as a post-translational modification. Disulphide bonds can either form within a single polypeptide chain (left) or between polypeptide chains in a multi-subunit protein complex (right).
References
Other websites
- Science aid: protein synthesis Archived 2007-02-12 at the Wayback Machine For high school
- Protein synthesis
- Transcription Archived 2006-12-14 at the Wayback Machine
- Translation Archived 2006-12-14 at the Wayback Machine
- Protein synthesis animation Archived 2007-10-21 at the Wayback Machine Wesleyan University Learning Objects animation of protein synthesis.
- Interactive Java simulation of transcription initiation. Archived 2011-07-22 at the Wayback Machine From Center for Models of Life Archived 2011-08-09 at the Wayback Machine at the Niels Bohr Institute.