| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Genetics and Molecular Biology |
Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA1
Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, WI 53706, USA2
Author for correspondence: James L. Steele. Tel: +1 608 262 5960. Fax: +1 608 262 6872. e-mail: jlsteele{at}facstaff.wisc.edu
Amino acid aminotransferases (ATases), which catalyse the last biosynthetic step of many amino acids, may have important physiological functions in Lactococcus lactis during growth in milk. In this study, the aspartate ATase gene (aspC) from L. lactis LM0230 was cloned by complementation into Escherichia coli DL39. One chromosomal fragment putatively encoding aspC was partially sequenced. A 1179 bp ORF was identified which could encode for a 393 aa, 43·2 kDa protein. The deduced amino acid sequence had high identity to other AspC sequences in GenBank and is a member of the I
family of ATases. Substrate-specificity studies suggested that the lactococcal AspC has ATase activity only with aspartic acid (Asp). An internal deletion was introduced into the L. lactis chromosomal copy of aspC by homologous recombination. The wild-type and mutant strain grew similarly in defined media containing all 20 amino acids and did not grow in minimal media unless supplemented with asparagine (Asn). The mutant strain was also unable to grow in or significantly acidify milk unless supplemented with Asp or Asn. These results suggest that only one lactococcal ATase is involved in the conversion of oxaloacetate to Asp, and Asp biosynthesis is required for the growth of L. lactis LM0230 in milk.
Keywords: Lactococcus lactis, lactic acid bacteria, aspartate aminotransferase, amino acid biosynthesis, aspartate biosynthesis
Abbreviations: Ap, ampicillin; ATase, aminotransferase; CFE, cell-free extract; Em, erythromycin; Opp, Lactococcus lactis oligopeptide transport system
The GenBank accession number for the sequence reported in this paper is AF035157
This article has been cited by other articles:
|
|
 |
|
  M. Liu, A. Nauta, C. Francke, and R. J. Siezen Comparative Genomics of Enzymes in Flavor-Forming Pathways from Amino Acids in Lactic Acid Bacteria Appl. Envir. Microbiol., August 1, 2008; 74(15): 4590 - 4600. [Full Text] [PDF]
|
|
|
|
|
|
S. Arioli, C. Monnet, S. Guglielmetti, C. Parini, I. De Noni, J. Hogenboom, P. M. Halami, and D. Mora Aspartate Biosynthesis Is Essential for the Growth of Streptococcus thermophilus in Milk, and Aspartate Availability Modulates the Level of Urease Activity Appl. Envir. Microbiol., September 15, 2007; 73(18): 5789 - 5796. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Derzelle, A. Bolotin, M.-Y. Mistou, and F. Rul Proteome Analysis of Streptococcus thermophilus Grown in Milk Reveals Pyruvate Formate-Lyase as the Major Upregulated Protein Appl. Envir. Microbiol., December 1, 2005; 71(12): 8597 - 8605. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Gitton, M. Meyrand, J. Wang, C. Caron, A. Trubuil, A. Guillot, and M.-Y. Mistou Proteomic Signature of Lactococcus lactis NCDO763 Cultivated in Milk Appl. Envir. Microbiol., November 1, 2005; 71(11): 7152 - 7163. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Monnet, D. Mora, and G. Corrieu Glutamine Synthesis Is Essential for Growth of Streptococcus thermophilus in Milk and Is Linked to Urea Catabolism Appl. Envir. Microbiol., June 1, 2005; 71(6): 3376 - 3378. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Chambellon and M. Yvon CodY-Regulated Aminotransferases AraT and BcaT Play a Major Role in the Growth of Lactococcus lactis in Milk by Regulating the Intracellular Pool of Amino Acids Appl. Envir. Microbiol., June 1, 2003; 69(6): 3061 - 3068. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
