base analogue

(redirected from nucleotide base)

base analogue

A chemical which resembles a purine or pyrimidine base, which differs slightly in structure from the normal bases found in nucleic acids (DNA or RNA) and, when intercalated in the nucleic acid, may alter one or more of its normal functions or cause point (single-base substitution) mutations.

Examples
Aminopurine (which replaces adenine), bromouracil (which replaces thymine), azaguanine, azauracil, 5-bromodeoxyuridine.

base analogue

Any compound structurally similar to a DNA BASE that can substitute for a base and thus cause a mutation.
Base analogueclick for a larger image
Fig. 62 Base analogue . The action of 5-bromouracil on DNA.

base analogue

any chemical that has a similar structure (i.e. is analogous) to one of the purine or pyrimidine bases in DNA or RNA. Such analogues can become incorporated into the nucleic acid and may act as a MUTAGEN. For example, 5-bromouracil (5Bu) is an analogue of thymine and can be incorporated into DNA in place of thymine. In its normal state 5Bu acts like thymine and pairs with adenine (see COMPLEMENTARY PAIRING but the analogue sometimes undergoes a chemical change called a tautomeric shift and now pairs with guanine. At the next DNA replication an incorrect base will be incorporated into the DNA, causing a TRANSITION SUBSTITUTION mutation (adenine - guanine).
References in periodicals archive ?
This situation can arise in the event of a tautomeric shift (transient rearrangement of a nucleotide base structure, allowing for non-canonical pairing) right as the polymerase comes by.
Caption: Short chains of adenosine monophosphate (AMP) --a nucleotide base for both DNA and RNA --can form the double helix shown above (the grey spheres represent ammonium ions.
At this particular site in the genome, 60 percent of individuals have the nucleotide base termed adenine (A) and 40 percent have the nucleotide base termed guanine (G).
This current is highly sensitive to the size and shape of the nanopore and in theory, each nucleotide base in the DNA thread will obstruct the nanopore as it migrates, altering the ionic current in a recognizable and reproducible way.
Characterization in all seven taxa revealed a variable size of CD36 gene [minimum of 29058 nucleotide base pair (bp) in M.
The benchmark test ran a standard Blast-n query to match 25 nucleotide base pairs against 600,000 queries.
In this context MALDI-TOF MS has been shown to permit the detection of paternally inherited single nucleotide base variations from fetal cf-DNA in maternal plasma (2) and donor-derived single-base variations (also known as single-nucleotide polymorphisms) in the urine of kidney transplant recipients (3).
The nucleotide base sequence of each product showed that each shared 100% similarity with sequences of other B.
The genetic information is contained in the double helix molecule of DNA, composed of nucleotide base pairs.
1) The application matched 20 nucleotide base pairs against 600,000 queries.
The incorporated dideoxynucleotide triphosphate (ddNTP) was complementary to the nucleotide base of interest (5) and acted as terminator in the extension reaction, producing a single-base difference of the extended products.
062 (18), employing the neighbor-joining search algorithm (minimum evolution) using maximum likelihood to estimate Ti:Tv ratio and nucleotide base frequencies (settings correspond to Hasegawa-Kishino-Yano [HKY] 1985 model of nucleotide sequence evolution).