Abstract:
:Deacetoxy/deacetylcephalosporin C synthase (acDAOC/DACS) from Acremonium chrysogenum is a bifunctional enzyme that catalyzes both the ring-expansion of penicillin N to deacetoxycephalosporin C and the hydroxylation of the latter to deacetylcephalosporin C. The R308 residue located in close proximity to the C-terminus of acDAOC/DACS was mutated to the other 19 amino acids. In the resulting mutant pool, R308L, R308I, R308T and R308V showed significant improvement in their ability to convert penicillin analogs, thus confirming the role of R308 in controlling substrate selectivity, the four amino acids all possess short aliphatic sidechains that may improve hydrophobic interactions with the substrates. The mutant R308I showed the highest reactivity for penicillin G, with 3-fold increase in k(cat)/K(m) ratio and 7-fold increase in relative activity.
journal_name
Biotechnol Lettjournal_title
Biotechnology lettersauthors
Wu XB,Tian XY,Ji JJ,Wu WB,Fan KQ,Yang KQdoi
10.1007/s10529-010-0504-5subject
Has Abstractpub_date
2011-04-01 00:00:00pages
805-12issue
4eissn
0141-5492issn
1573-6776journal_volume
33pub_type
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