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]
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]
NlaIII isoschizomers recognize and cut the same recognition sequence 5’-CATG-3’.[11] Endonucleases that cut at this sequence include:
NlaIII can be used in many different experimental procedures[12] such as: