NlaIII is a type II
restriction enzyme isolated from
Neisseria lactamica.[1] As part of the
restriction modification system, NlaIII is able to prevent foreign DNA from integrating into the host genome by cutting double stranded DNA into fragments at specific sequences.[2] This results in further degradation of the fragmented foreign DNA and prevents it from infecting the host genome.[3]
NlaIII recognizes the
palindromic and complementary DNA sequence of CATG/GTAC and cuts outside of the G-C base pairs. This cutting pattern results in
sticky ends with GTAC overhangs at the
3' end.[4]
Characteristics
NlaIII from N. lactamica contains two key components: a methylase and an endonuclease.[5] The methylase is critical to recognition, while the endonuclease is used for cutting.[5] The gene (NlaIIIR) is 693 bp long and creates the specific 5’-CATG-3’ endonuclease.[6] A homolog of NlaIIIR is iceA1 from
Helicobacter pylori.[6] In H. pylori, there exists a similar methylase gene called hpyIM which is downstream of iceA1.[7]ICEA1 is an endonuclease that also recognizes the 5’-CATG-3’ sequence.[6]IceA1 in H. pylori is similar to that of NlaIII in N. lactamica.
NlaIII contains an ICEA protein that encompasses the 4 to 225 amino acid region.[6][8]H. pylori also contains the same protein.[9]H. pylori infection often leads to gastrointestinal issues such as peptic ulcers, gastric adenocarcinoma and lymphoma.[10] Researchers speculate that ICEA proteins serve as potential markers for gastric cancer [7]
Isoschizomers
NlaIII
isoschizomers recognize and cut the same recognition sequence 5’-CATG-3’.[11] Endonucleases that cut at this sequence include:
Fael
Fatl
Hin1II
Hsp92II
CviAII
IceA1
Applications
NlaIII can be used in many different experimental procedures[12] such as: