amlC, Another amylolytic gene maps close to the amlB locus in Streptomyces lividans TK24

Abstract The region located upstream of the α -amylase gene ( amlB ) of Streptomyces lividans TK24 ( Yin et al., 1997 ) contains a 2978-bp-long ORF divergent from amlB, and designated amlC . amlC Encodes a 993 amino acid (aa) protein with a calculated molecular weight of 107.054 kDa. On the basis of sequence similarity as well as enzymatic activity, AmlC is likely to belong to the 1,4- α - d -glucan glucanohydrolase family. amlC is transcribed as a unique 3 kb leaderless monocistronic mRNA. Primer extension experiments allowed the identification of promoter sequences that do not resemble the typical eubacterial promoter sequences. amlC was successfully disrupted and was mapped at approx. 700 kb from a chromosomal end of S. lividans TK24, 100 kb on the right of the amplifiable unit AUD1 ( Volff et al., 1996 ). Nevertheless, amlC disruption seemed to be accompanied by extensive rearrangements of the 2500-kb Dra I–II fragment of the chromosome.