Reading frames

If you re not sure of the mechanism of acetal formation or just want to know a bit more about acetals, read frames 1-21 and 62-64 of the Carbonyl Programme. 

As the complete genomes of more and more species are sequenced, the determination of the function of previously unidentified open reading frames is becoming an increasing and challenging problem. The possibility of... 

The cDNA encoding the luciferase of Renilla reniformis has been obtained and expressed in Escherichia coli (Lorenz et al., 1991). The cDNA contained an open reading frame encoding a 314-amino acid sequence. The recombinant Renilla luciferase obtained had a molecular weight of 34,000, and showed an emission maximum at 480 nm in the luminescence reaction of coelenterazine, in good agreement with the data of natural Renilla luciferase. 

Neuronal NO synthase (nNOS) is constitutively expressed in neurons of the brain. Its activity is regulated by Ca2+ and calmodulin. Half-saturating L-arginine concentrations are around 2 pM. cDNAs encoding nNOS have been cloned from rat and human brain. The open reading frame of human nNOS consists of 4299 bp, corresponding to 1433 aa. This predicts a protein of 160 kDa, which is in accordance with the molecular mass of the purified protein. 

An opening frame contains a series of codons (base triplets) coding for amino acids without any termination codons. There are six potential reading frames of an unidentified sequence. 

Fig. 2 The HBV polymerase and envelope proteins, whose reading frames overlap each other, and position of the main HBV drug-resistant mutations...

Computer algorithms facilitate identification of the open reading frames that encode a given protein by using partial sequences and peptide mass profiling to search sequence databases. 

Initiation of protein synthesis requires that an mRNA molecule be selected for translation by a ribosome. Once the mRNA binds to the ribosome, the latter finds the correct reading frame on the mRNA, and translation begins. This process involves tRNA, rRNA, mRNA, and at least ten eukaryotic initiation factors (elFs), some of which have multiple (three to eight) subunits. Also involved are GTP, ATP, and amino acids. Initiation can be divided into four steps (1) dissociation of the ribosome into its 40S and 60S subunits (2) binding of a ternary complex consisting of met-tRNAf GTP, and eIF-2 to the 40S ribosome to form a preinitiation complex (3) binding of mRNA to the 40S preinitiation complex to form a 43S initiation complex and (4) combination of the 43S initiation complex with the 60S ribosomal subunit to form the SOS initiation complex. 

The open reading frame of the mRNA is the series of codons, each specifying a certain amino acid, that determines the precise amino acid sequence of the protein. 

DNA sequencing Establishes the highest resolution physical map. Identifies open reading frame. Facilities with many high throughput instruments could sequence millions of base pairs per day. 

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