PTMs are also important for allowing the recycling of proteins if they are no longer needed - a critical example of this is in the cell cycle where regulators for some the stages must be broken down to allow the next stage to proceed normally. This has multiple advantages - for example, this saves cells energy and time (synthesizing new mRNAs and then proteins is energy intensive and slow compared with making PTMs). Attenuation can add another 10 fold decrease in expression.īoth mechanisms thus work together to give a better level of control.Ģ) Post-translational modifications (PTMs) have the additional advantage of often being reversible - you don't need to make new proteins a cell can just fine tune their activity as needed. Duplication of the exons encoding structural domains and subsequent recombination can lead to more rapid evolution of a new protein, essentially using the parts from. Introns tend to occur between those portions of genes that encode structural domains of proteins. Amino acid sequences were aligned using MacVector 7.2 (Accelrys) and.
coli trp operon the repressor is reported to decrease expression by about 70 fold. The exon organization tends to be well conserved in highly divergent species. We sought to analyze the evolution of sequence and exon-intron structure of a. Good question, but too complex to answer completely here - I'll give you a few advantages, but I encourage you to read more about this subject on your own.ġ) Biological systems are quite error prone, so overlapping mechanisms often are used to achieve tighter control.įor example, in the E.
0 kommentar(er)
