DNA consists

DNA consists of many deoxidization nucleotide sequence according to certain residue, each with 3-5 phosphate ester key of long chain connected. Most of the DNA contains two such long chain, and some results, such as DNA, e. coli X174 suits G4, phage M13 etc. Some DNA, DNA for circular for linear. Mainly contains adenine and guanine and thymine bases cytosine and four bases. In certain types of DNA methylation cytosine, 5 - in a certain extent, which replaced cytosine wheat embryo DNA methylation cytosine 5 - especially rich, up to 6 percent. Moore In some phage, 5 - n-hydroxymethyl cytosine replaced cytosine. The 1940s, hargaff guthrie E.C (that) of different species of DNA bases are different, but the number of adenine is equal to the number of thiamine (= T), guanine is equal to the number of cytosine (G = C), and number of equal to number of pyrimidines). Generally depicted in several layers structure of DNA.
The primary structure of DNA level structure is the base sequence. Gene is a segment of DNA genetic information storage, gene in its base in sequence. 1975 American gilbert W.G (UK) and the sanger ilbert F.S (anger) founded the DNA level structure of rapid determination methods, 1980 year of their chemistry prize. Since then, and constantly improve measurement method, the primary structure of DNA has many established. If people mitochondrial DNA contains a ring that 16569, lambda phage DNA contains a base pairs, rice 48502 134525 containing a base pairs chloroplasts genome, tobacco chloroplasts genome contains 155844 a base pairs, etc. Now, the United States has 10 to 15 years in human DNA molecules in about 30 billion for all nucleotide sequence of determination.
Secondary structure in 1953, Watson and Crick (Watson) Crick (.) the basic structure of DNA double helix fiber structure, then this is recognized by scientists model, and the explanation for replication, and other important transcription process of life. For the further research, humidity and base sequences that etc, DNA double helix can have many types, mainly divided into A and B and Z three categories.
Generally, the closest to the cell B configuration of DNA double helix conformation, it is very similar to model. DNA and RNA molecule - the double helix area and the formation of transcription DNA molecule hybridization RNA conformation close -. Z - DNA to nucleotide dimers for unit, the Lord left to wound is serrated (Z) chain, the name. This configuration for a nucleotide chain of purine cytosine alternate area. In 1989, the American scientists scanning tunneling microscopy method directly observed double-helix DNA double-helix DNA in 1952, Austria, African American biochemist captains E.c hargaff gadamer check (1905 -), the four determination of DNA base, the content of fat poison and found adenocarcinoma of the number of thymine bases, bird whisper fat with equal the number of cytosine. This makes Watson and crick immediately thought of four bases exist between two corresponding relationship, formed the glands and thymine * matching belt whisper, birds and cytosine matching belt whisper.
Senior structure
Three chain DNA (T) DNA -
In the early 1950s Wilkins, according to the X-ray diffraction picture once thought DNA may have 3 chains, then Watson and Crick also have some of the construction of DNA model,. The three chain DNA can be classified into two categories, namely three strands of spiral structure and BaiChunLi etc in 1990 by scanning electron tunneling microscopy techniques observed three strands of ornaments structure."
Three strands of DNA double helix spiral structure is formed on the basis of the structure of the chain, three chains are cognate 3) or homologous thymine bases that whole of purine or cytosine, according to article 3 source of chain can be divided into three chain DNA molecules in between two groups and the molecular chain consisting of three, according to the relative positions and can be divided into the Pu - Pu - Py and Py - Pu Py - two type (Pu generation
Table purine chain, Py represents one of the most common pyrimidines chain is Py - Pu Py - 3, it has two chains for normal double helix, located in article 3 of the double helix pyrimidines chains, and the chains purine ditch, and the direction of the double helix structure rotates with three chain base pairing with the same way, double-helix DNA base on A - it is still, G - C matching T, but the first 3 chain of C, and it must be formed with only 2 hydrogen G (normally three hydrogen).
Three chains to the further study of DNA to eukaryotic chromosomes structure and the gene transcriptional regulation and restructuring, copying, the mechanism. Three chain of DNA is available, such as application value liquid.thus DNA fragments will cut (such as the nucleic acid enzymes) carry specific locus of DNA, and to achieve a break, and the purpose of chromosomes of DNA cells for transcription factors etc. double-helix DNA and protein only after the combination can open the specific gene transcription, but three strands and transcription factors, thus available spiral oligonucleotides gather DNA fragments of the closed transcription factor sites, so as to achieve closed harmful genes or virus gene.
Four chain body DNA
In the simulated Sundpuist Klug and 1 protoctistans spines caterpillars telomeres, synthetic DNA sequence of DNA 1, found in certain conditions of simulation results can be formed DNA G four chain structure of DNA body. Hence infer telomere liquid.thus the chromosome chain between four and formed. Such people with Kang respectively in the crystal and experiments, rich in the solution to four DNA G chain structure of DNA body.
Four basic structure of DNA chain body is G - 4 in four conjoined twin conjoined twins, the center is one of four with negative oxygen into the "carboxylic through G - 4 pocket" of conjoined twins or molecules can form of DNA double helix, and right spiral structure of conjoined twins, G - 4 with two spiral distinct characteristics: 1, it depends on the stability of cation in pocket, known species of k to four conjoined twin screw is the most stable, 2, thermodynamics and kinetics of its nature is very stable.
As for some biological sequences of DNA analysis and guanine sequences of DNA in some in function and evolution of the genome are fairly conservative regional, many studies show that rich guanine DNA formed G - as molecular DNA may mutual recognition of the components in biological cells, plays a special role