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Restriction
enzymes also called Restriction endonuclease are proteins
produced by bacteria that cleave DNA at specific sites
along the molecule. In the bacterial cell, restriction
enzymes cleave foreign DNA, thus eliminating infecting
organisms. Restriction enzymes can be isolated from bacterial
cells and used in the laboratory to manipulate fragments
of DNA, such as those that contain genes; for this reason
they are indispensable tools of recombinant DNA technology.
REB, a Restriction Enzyme Database is a comprehensive
database which gives the complete information about restriction
enzymes, methyltranferases and related proteins involved
in the process of restriction modification.
REB
List:
The REB List gives
an overview of all the services provided by REB. It is
divided into two groups, the REB Main List and
REB specificities.
The REB Main List gives the basic information about restriction
enzymes like their types and subtypes while the REB Specificities
provides you with the specialized information about restriction
enzymes and their related proteins expedient for research.
Click on the link provided for detailed information.
REB
Tool:
The Reb Tool is a
user friendly and easy to use multitask tool which has
a number of features.
Enter any nucleotide sequence and the REB tool provides
you with all the commercially important enzymes which
cut the nucleotide sequence given by you.
It also give the possible reading freames and the A-T,G-C
content of the input sequence
REB
Enzymes:
The REB Enzymes provides
you with the profound information about more than four
thousand restriction enzymes . Click on to any enzyme
of your choice and the detailed information about the
enzyme will be displayed.
REB
Search:
The REB Search is
an efficient search engine which navigates you to the
enzyme of your choice.
Enter any keyword preferably the enzyme name, organism,
recognition sequence,optimum temperature or subtype in
the space provided and the appropriate enzyme with its
details will be displayed.
REB
FAQ's:
Though the REB has been developed in a very user friendly
manner it is quite poissible that you may come up with
questions regarding Restriction enzyme or REB. To find
the answers to your questions, the REB
FAQ's is enlisted
with some of the most frequently asked questions about
Restriction enzymes and REB. If by chance you sill have
doubt you can send in your querries and feedback at link
named 'Feedback' on the home page.
REB
Glossary:
The REB Glossary
provides you with the definition of terms used in REB
which you may find difficult to understand. It is enlisted
with some of the basic terminologies used in Reb to give
you a better understanding and indepth knowledge of Restriction
Enzymes.
Recognition
Sequence:
Certain enzymes have their own characteristic recognition
sequences which may be denoted by alphabets other than
A,T,G and C. The REB gives the standard abbreviation of
all recognition sites
(Eur. J. Biochem. 150: 1-5, 1985) to represent
ambiguity:
R
= G or A
Y
= C or T
M = A or C
K = G or T
S = G or C
W = A or T
B = not A (C or G or T)
D = not C (A or G or T)
H = not G (A or C or T)
V = not T (A or C or G)
N = A or C or G or T
These
are written from 5' to 3', when only one strand is shown.
Typically, the recognition sequences are oriented so that
the cleavage sites lie on their 3' side.
Enzymes
that cleave away from their recognition Sequence:
For enzymes such as HgaI, MboII etc., which cleave
away from their recognition sequence, the cleavage sites
are indicated in parentheses.
For example HgaI GACGC (5/10) indicates cleavage as follows:
5'
GACGCNNNNN^ 3'
3' CTGCGNNNNNNNNNN^ 5'
Enzymes
with unusual cleavage properties:
Enzymes that cut on both sides of their recognition
sequences, such as BcgI, Bsp24I, CjeI and CjePI, have
4 cleavage sites each instead of 2.
Bsp24I
5'
^NNNNNNNNGACNNNNNNTGGNNNNNNNNNNNN^ 3'
3' ^NNNNNNNNNNNNNCTGNNNNNNACCNNNNNNN^ 5'
This will be described in some REB as: Bsp24I (8/13)GACNNNNNNTGG(12/7)
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