MamI, a novel class-II restriction endonuclease from Microbacterium ammoniaphilum recognizing 5'-GATNN decreases NNATC-3'.
A new site-specific class-II restriction endonuclease, MamI, has been discovered in the nonsporulating Gram+ Microbacterium ammoniaphilum. MamI recognition sequence and cleavage positions were deduced using experimental and computer-assisted mapping and sequencing approaches. MamI cleavage specificity corresponds to: [formula: see text] The novel 43-kD enzyme recognizes a palindromic hexanucleotide interrupted by four ambiguous nucleotides. MamI cleavage positions are located in the center of the recognition sequence resulting in blunt-ended fragments after cleavage in the presence of Mg2+ ions. MamI is inhibited by N6-methyladenine residues. In case of overlapping sequences of MamI and Escherichia coli-coded DNA modification methyltransferase M.EcodamI (5'-[formula: see text]-3'), cleavage of DNA isolated from E. coli wild-type cells will be inhibited. By applying incubation conditions forcing star activity, relaxing of MamI sequence specificity is observed (MamI*).
Boehringer Mannheim GmbH, Biochemical Research Center, Dept. of Genetics, Penzberg, F.R.G.
H M
HM
Striebel
G G
GG
Schmitz
K
K
Kaluza
M
M
Jarsch
C
C
Kessler
D001483:Base Sequence; D015252:Deoxyribonucleases, Type II Site-Specific / Q000302:isolation & purification / Q000378:metabolism*; D006094:Gram-Positive Bacteria / Q000201:enzymology*; D008969:Molecular Sequence Data; D010957:Plasmids; D013379:Substrate Specificity
C064059:endodeoxyribonuclease BsaAI; D015252:Deoxyribonucleases, Type II Site-Specific