Identification and functional analysis of the gene encoding methionine-gamma-lyase in Brevibacterium linens.
The enzymatic degradation of L-methionine and subsequent formation of volatile sulfur compounds (VSCs) is believed to be essential for flavor development in cheese. L-methionine-gamma-lyase (MGL) can convert L-methionine to methanethiol (MTL), alpha-ketobutyrate, and ammonia. The mgl gene encoding MGL was cloned from the type strain Brevibacterium linens ATCC 9175 known to produce copious amounts of MTL and related VSCs. The disruption of the mgl gene, achieved in strain ATCC 9175, resulted in a 62% decrease in thiol-producing activity and a 97% decrease in total VSC production in the knockout strain. Our work shows that L-methionine degradation via gamma-elimination is a key step in the formation of VSCs in B. linens.
Amarita
Felix
F
Unité Mixte de Recherches Génie et Microbiologie des Procédés Alimentaires, Institut National de la Recherche Agronomique, Thiverval-Grignon, France.
Yvon
Mireille
M
Nardi
Michele
M
Chambellon
Emilie
E
Delettre
Jerôme
J
Bonnarme
Pascal
P
D000595:Amino Acid Sequence; D001951:Brevibacterium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013437:Carbon-Sulfur Lyases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002611:Cheese / Q000382:microbiology*; D017353:Gene Deletion; D008715:Methionine / Q000378:metabolism; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013457:Sulfur Compounds / Q000378:metabolism; D014835:Volatilization
D013438:Sulfhydryl Compounds; D013457:Sulfur Compounds; C005231:methylmercaptan; D008715:Methionine; D013437:Carbon-Sulfur Lyases; C021558:L-methionine gamma-lyase