| leader sequence | <molecular biology> In the regulation of gene expression for enzymes concerned with amino acid synthesis in prokaryotes, the leader sequence codes for the leader peptide that contains several residues of the amino acid being regulated. Transcription is closely linked to translation and if translation is retarded by limited supply of amino acyl tRNA for the specific amino acid, the mode of transcription of the leader sequence permits full transcription of the operon genes, otherwise complete transcription of the leader sequence prematurely terminates transcription of the operon. (18 Nov 1997) |
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| leader sequences | Sequences at the end of either nucleic acids (DNA and RNA) or proteins that must be processed off to allow for a specific function of the mature molecule. (05 Mar 2000) |
| leader | A sequence near the 5' end of an RNAstrand or the amino terminus of a protein that functions intargeting or regulation. (09 Oct 1997) |
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| leader peptide | <molecular biology> In the regulation of gene expression for enzymes concerned with amino acid synthesis in prokaryotes, the leader sequence codes for the leader peptide that contains several residues of the amino acid being regulated. Transcription is closely linked to translation and if translation is retarded by limited supply of amino acyl tRNA for the specific amino acid, the mode of transcription of the leader sequence permits full transcription of the operon genes, otherwise complete transcription of the leader sequence prematurely terminates transcription of the operon. (18 Nov 1997) |
| alu sequence | Any of a family of short (300 basepairs long) repeated sequences that occur throughout the human genome. (09 Oct 1997) |
| amino acid sequence | The sequence of amino acids as arrayed in chains, sheets, etc., within the protein molecule. This is referred to as the primary structure of proteins. It is of fundamental importance in determining protein conformation. (12 Dec 1998) |
| autonomously replicating sequence | <molecular biology> This is a chromosomal sequence that allows plasmids to replicate on their own in yeast. (02 Jan 1998) |
| base sequence | <molecular biology> The order of nucleotide bases in a DNA molecule. (09 Oct 1997) |
| base sequence analysis | <molecular biology> A method, sometimes automated, for determining the base sequence. (09 Oct 1997) |
| canonical sequence | Of a series of related DNA, RNA or protein sequences, the sequence that reflects the most common choice of base or amino acid at each position. Areas of particularly good agreement often represent conserved functional domains. The generation of consensus sequences has been subjected to intensive mathematical analysis. (18 Nov 1997) |
| carbohydrate sequence | The sequence of carbohydrates within polysaccharides, glycoproteins, and glycolipids. (12 Dec 1998) |
| palindromic sequence | <molecular biology> Nucleic acid sequence that is identical to its complementary strand when each is read in the correct direction (e.g. TGGCCA). Palindromic sequences are often the recognition sites for restriction enzymes. Degenerate palindromes with internal mismatching can lead to loops or hairpins being formed (as in tRNA). (18 Nov 1997) |
| recognition sequence | A nucleotide sequence --typically composed of 4, 6, or 8nucleotides -- that is recognised by a restriction endonuclease. Type II enzymes cut (and theircorresponding modification enzymes methylate) within or very near the recognition sequence. (09 Oct 1997) |
| regulatory sequence | <molecular biology> DNA sequence to which regulatory molecules such as promotors or enhancers bind, thereby altering the expression of the adjacent gene. (18 Nov 1997) |
| centromeric sequence | <molecular biology> Special sequences of DNA nucleotides found on chromosomes which provide a site for the attachment of spindle fibres during nuclear division (mitosis or meiosis). (09 Oct 1997) |
| chi sequence | <molecular biology> A specific sequence of nucleotides on a site on the genome of the bacteria Escherichia coli which strongly encourages recombination and crossing over to occur at that site. (05 Jan 1998) |
| PEST sequence | Amino acid motif that is thought to target cytoplasmic proteins for rapid proteolytic degradation. (18 Nov 1997) |