ThesacBandsacCgenes encoding levansucrase and sucrase form a gene cluster inZymomonas mobilis

✍ Scribed by P. Gunasekaran; G. Mukundan; R. Kannan; S. Velmurugan; N. Aït-Abdelkader; E. Alvarez-Macarie; J. Baratti

• Publisher: Springer Netherlands
• Year: 1995
• Tongue: English
• Weight: 626 KB
• Volume: 17
• Category: Article
• ISSN: 0141-5492
• DOI: 10.1007/bf00129392

✦ Synopsis

The Zymomonas mobilis gene sacB that encodes the extracellular levansucrase was cloned and expressed in Escher~chia coli. The gene product exhibited both sucrose hydrolysis activity and levan forming capability. Sub-cellular fractionation ofE. coli carrying pLSS41 revealed that about 95% of the total sucrase activity was detected in the cytoplasmic fraction. The levansucrase gene was overexpressed (about hundred fold) in E. coti under T7 polymerase expression system. Nucleotide sequence analysis of this gene revealed an open reading frame of 1269 bp long coding for a protein of 423 amino acids with a molecular mass of 46.7 KDa. The deduced amino acid sequence was identical to the N-terminal amino acids of protein A51 ofZ. mobilis ZM4. Therefore, the product ofsacB is levansucrase. This is the first extracellular enzyme of Z. mobilis sequenced which does not possess a signal sequence.This gene is located 198 bp upstream ofsacC gene encoding for the extracellular sucrase forming a gene cluster