5.2 Protein of unknown function similar to proteins from other organisms.

Members of Phosphoribosyltransferase (PRT) are catalytic and are regulatory proteins involved in nucleotide synthesis and salvage. Not all PRT proteins are enzymes. For example, in some bacteria PRT proteins regulate the expression of purine and pyrimidine synthetic genes.

6 Protein of unknown function, without similarity to other proteins.

RecA (Recombinase A); Can catalyze the hydrolysis of ATP in the presence of single- stranded DNA, the ATP-dependent uptake of single-stranded DNA by duplex DNA, and the ATP-dependent hybridization of homologous single-stranded DNAs. It interacts with LexA causing its activation and leading to its autocatalytic cleavage; Belongs to the RecA family.

Magnesium chelatase, subunit ChlI; Magnesium-chelatase is a three-component enzyme that catalyses the insertion of Mg2+ into protoporphyrin IX.

DNA topoisomerase I; Releases the supercoiling and torsional tension of DNA, which is introduced during the DNA replication and transcription, by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA- (5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand, thus removing DNA supe [...]