02569nas a2200361   4500000000100000008004100001260001300042653002400055653001200079653002400091653001800115653001100133653002300144653001900167653002100186653001100207653001200218653002800230653002400258653002400282653002300306653003400329100001100363700001200374700001800386700001500404700001400419245009500433300001100528490000700539520164700546022001402193       1995                            d  c1995 Jul10aAmino Acid Sequence10aAnimals10aAntigens, Bacterial10aBase Sequence10aCattle10aCloning, Molecular10aDNA, Bacterial10aGenes, Bacterial10aHumans10aleprosy10aMolecular Sequence Data10aMycobacterium bovis10aRestriction Mapping10aSequence Alignment10aSequence Homology, Amino Acid1 aBigi F1 aAlito A1 aFisanotti J C1 aRomano M I1 aCataldi A00aCharacterization of a novel Mycobacterium bovis secreted antigen containing PGLTS repeats.  a2581-60 v633 a<p>Serum from naturally infected cattle was used to identify a novel Mycobacterium bovis antigen from an expression library. The first recombinant product identified was a fusion protein with lacZ (55 kDa). A clone containing the whole gene was also obtained. This clone expressed a 38-kDa protein. A rabbit serum against the recombinant antigen reacts in M. bovis supernatants with two proteins of 36 and 34 kDa. The new protein was called P36/P34. The gene cloned has a deduced amino acid sequence with a predicted molecular mass of 28 kDa, showing a characteristic signal sequence for exportation. The protein bears partial homology to a 28-kDa protein from M. leprae. An interesting feature of the P36/P34 sequence is that it contains several PGLTS repeats, which are not present in the M. leprae protein. Antigenic determinants seem also to be conserved between the two proteins because sera from leprosy patients recognized the recombinant M. bovis protein. The discrepancy among the molecular mass deduced from the sequence (28 kDa), that of the recombinant protein in Escherichia coli (38 kDa), and that of the native protein in M. bovis (36 and 34 kDa) could be attributed to posttranslational modifications or to the high proline content that may alter the migration properties of the protein. This antigen seems to be immunodominant during bovine tuberculosis, because 8 of 9 serum specimens from diseased cattle are reactive. The homology among the M. leprae 28-kDa protein, the protein described in this article, and a recently described M. tuberculosis protein suggests the existence of a new protein family in mycobacteria.</p>  a0019-9567