Search results for "Genetic code"

Adaptive antioxidant methionine accumulation in respiratory chain complexes explains the use of a deviant genetic code in mitochondria

2008

Humans and most other animals use 2 different genetic codes to translate their hereditary information: the standard code for nuclear-encoded proteins and a modern variant of this code in mitochondria. Despite the pivotal role of the genetic code for cell biology, the functional significance of the deviant mitochondrial code has remained enigmatic since its first description in 1979. Here, we show that profound and functionally beneficial alterations on the encoded protein level were causative for the AUA codon reassignment from isoleucine to methionine observed in most mitochondrial lineages. We demonstrate that this codon reassignment leads to a massive accumulation of the easily oxidized …

On the dimerization of the primitive tRNAs: implications in the origin of genetic code.

2002

RNAs that catalyse their own aminoacylation have been recently selected in vitro. These findings support the notion that the primitive aminoacyl-tRNA synthetases may have been RNAs. In this paper, we propose a structural model for the first aminoacyl-tRNA synthetase consisting of an RNA complex formed between two primitive tRNA molecules through two intermolecular loop-strand interactions, and with implications in the origin of the genetic code.

Redox Biochemistry of the Genetic Code.

2021

New findings on the chemistry of the amino acids, their role in protein folding, and their sequential primordial introduction have uncovered concealed causalities in genetic code evolution. The genetically encoded amino acids successively provided (i) membrane anchors, (ii) halophilic protein folds, (iii) mesophilic protein folds, (iv) metal ligation, and (v) antioxidation.

Chloroplastic glutamine synthetase from Brassica napus.

1993

Nucleic Acids and Nuclear Proteins

1994

DNA deserves the most attention in any book dealing with molecular variety in animals. The complete genetic information of the organism is encoded in the order of the bases, and with it also is the whole spectrum of genetically determined variation within and between individuals. One can view DNA as a text in which each of the four letters at each position has a unique meaning. Some information and variety is lost en route from the DNA via RNA to the proteins and the complex morphological and physiological characters because only part of the DNA is transcribed into RNA, and not all RNA codes for proteins; furthermore, the genetic code is degenerate and the 64 possible triplet codons define …

An Epigenetic Alphabet of Crop Adaptation to Climate Change

2022

Crop adaptation to climate change is in a part attributed to epigenetic mechanisms which are related to response to abiotic and biotic stresses. Although recent studies increased our knowledge on the nature of these mechanisms, epigenetics remains under-investigated and still poorly understood in many, especially non-model, plants, Epigenetic modifications are traditionally divided into two main groups, DNA methylation and histone modifications that lead to chromatin remodeling and the regulation of genome functioning. In this review, we outline the most recent and interesting findings on crop epigenetic responses to the environmental cues that are most relevant to climate change. In additi…