Disease relevance of ORF2

• The product of ORF2 (191 residues) was related to the resolvase of Tn917 (33% amino acid identity) and to the Res protein (48%) of plasmid pIP404 from Clostridium perfringens [1].
• In the absence of a functional ORF2 polypeptide the toxin does not form the crystalline inclusions characteristic of other known Bacillus thuringiensis toxins [2].
• Finally, the 270 residue pGI2 ORF2 was shown to be related to ORF43 of pMRC01, a 60 kb conjugative plasmid from Lactococcus lactis subsp. lactis [3].

High impact information on ORF2

• Insertional inactivation demonstrated that orf2 is necessary for zwittermicin A production and that zmaR is necessary for high-level resistance to zwittermicin A but is not required for zwittermicin A production [4].
• Analysis of sequence data reveals that pOM1 contains only two open reading frames of significant length (ORF1 and ORF2), both of which are required for self-replication and maintenance [5].
• The putative translation product of ORF2, on the other hand, resembles Rep (replication) proteins of a different group of gram-positive plasmids, for which the Staphylococcus plasmid pSN2 is a prototype [5].
• The ORF2 amino acid sequence is similar to that of the carboxy terminus of Cry4 proteins [6].
• Two small open reading frames of unknown function, designated orf1 (85 residues) and orf2 (74 residues), were also identified [7].

Biological context of ORF2

• It was 261 base pairs in length, located in the open reading frame 2 (ORF2) of BTSPB sequence [8].
• DNA sequence analysis indicates that cryB1 is the distal gene of an operon which is comprised of three open reading frames (designated orf1, orf2, and cryB1) [9].

Analytical, diagnostic and therapeutic context of ORF2

• Formation of crystals of foreign proteins (due to hyperexpression and folding by the putative chaperonin, ORF 2) provides a simple method of purification by centrifugation and enhances stability by protection from cellular proteases [10].
• Cellular localization and characterization of the Bacillus thuringiensis Orf2 crystallization factor [11].

References