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Related Concept Videos

Improving Translational Accuracy02:07

Improving Translational Accuracy

Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
Improving Translational Accuracy02:07

Improving Translational Accuracy

Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
Point and Frameshift Mutations01:30

Point and Frameshift Mutations

Point mutations are genetic alterations involving the change of a single nucleotide base pair in DNA. Depending on how the alteration affects protein synthesis, they can lead to various consequences.Point mutations fall into the following types:Silent mutations occur when a nucleotide change does not alter the amino acid sequence due to the redundancy of the genetic code. For instance, changing ACC to ACA still encodes threonine, leaving the protein function unaffected. This occurs because...
tRNA Activation02:26

tRNA Activation

Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
Transfer RNA Synthesis02:36

Transfer RNA Synthesis

One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...

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De novo Identification of Actively Translated Open Reading Frames with Ribosome Profiling Data
08:23

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Published on: February 18, 2022

An improved implementation of codon adaptation index.

Xuhua Xia1

  • 1Department of Biology and Center for Advanced Research in Environmental Genomics, University of Ottawa, 30 Marie Curie, P.O. Box 450, Station A, Ottawa, Ontario, Canada, K1N 6N5. xxia@uottawa.ca

Evolutionary Bioinformatics Online
|May 23, 2009
PubMed
Summary
This summary is machine-generated.

The codon adaptation index (CAI) measures gene expression but has biases. This study presents an improved CAI computational method that more accurately predicts protein production, enhancing gene expression analysis.

Keywords:
Codon usage biasgene expressiontRNAtranslation elongation

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Area of Science:

  • Bioinformatics
  • Molecular Biology
  • Computational Biology

Background:

  • The Codon Adaptation Index (CAI) is crucial for assessing gene expression and translation efficiency.
  • Existing computational methods for CAI calculation suffer from systematic biases, limiting their accuracy.
  • Accurate prediction of protein production is vital in synthetic biology and genetic engineering.

Purpose of the Study:

  • To identify and illustrate the systematic biases in current codon adaptation index implementations.
  • To develop and present a novel, improved computational method for calculating CAI.
  • To demonstrate the enhanced predictive power of the improved CAI for protein production.

Main Methods:

  • Analysis of systematic errors in existing CAI algorithms.
  • Development of a new algorithm to address identified biases.
  • Comparative evaluation of the improved CAI against standard implementations using experimental data.

Main Results:

  • Specific computational problems and biases in current CAI implementations were identified and explained.
  • A refined computer implementation for CAI calculation was developed.
  • The improved CAI demonstrated superior accuracy in predicting protein production compared to existing methods.

Conclusions:

  • Current codon adaptation index implementations contain significant biases affecting gene expression analysis.
  • The developed improved CAI offers a more reliable tool for predicting translation efficiency and protein production.
  • This advancement has implications for optimizing gene expression in various biological applications.