- Structural and stereochemical analysis of a modular polyketide synthase ketoreductase domain required for the generation of a cis-alkene
-
The formation of an activated cis-3-cyclohexylpropenoic acid by Plm1, the first extension module of the phoslactomycin polyketide synthase, is proposed to occur through an L-3-hydroxyacyl-intermediate as a result of ketoreduction by an A-type ketoreductase (KR). Here, we demonstrate that the KR domain of Plm1 (PlmKR1) catalyzes the formation of an L-3-hydroxyacyl product. The crystal structure of PlmKR1 revealed a well-ordered active site with a nearby Trp residue characteristic of A-type KRs. Structural comparison of PlmKR1 with B-type KRs that produce D-3-hydroxyacyl intermediates revealed significant differences. The active site of cofactor-bound A-type KRs is in a catalysis-ready state, whereas cofactor-bound B-type KRs are in a precatalytic state. Furthermore, the closed lid loop in substrate-bound A-type KRs restricts active site access from all but one direction, which is proposed to control the stereochemistry of ketoreduction.
- Bonnett, Shilah A.,Whicher, Jonathan R.,Papireddy, Kancharla,Florova, Galina,Smith, Janet L.,Reynolds, Kevin A.
-
p. 772 - 783
(2013/07/26)
-
- Aldol-type reactions of unmasked iodoacetic acid with carbonyl compounds promoted by samarium diiodide: Efficient synthesis of carboxylic 3-hydroxyacids and their derivatives
-
An easy, direct, general, and efficient samarium diiodide-mediated preparation of 3-hydroxyacids 1 in high yield by reaction of different aldehydes or ketones with commercially available iodoacetic acid is described. The application of different esterific
- Concellon, Jose M.,Concellon, Carmen
-
p. 4428 - 4432
(2007/10/03)
-
- Selective transformation of nitriles into amides and carboxylic acids by an immobilized nitrilase
-
Using an immobilized nitrilase from Rhodococcus sp. mild and selective hydrolysis of nitriles can be achieved even in the presence of acid or base sensitive groups under neutral conditions. This method is applicable to a broad range of substrates as exemplified by aliphatic, alicyclic, heterocyclic and carbohydrate type nitriles.
- Klempier,De Raadt,Faber,Grieng
-
p. 341 - 344
(2007/10/02)
-
- The Reaction of Trialkylvinylborate with Carbon Dioxide. A New Method for the Preparation of β-Hydroxycarboxylic Acids from Alkenes
-
Chloromagnesium trialkylvinylborate, (R3BCH=CH2)MgCl, on reaction with carbon dioxide under pressure, followed by oxidation with alkaline hydrogen peroxide, gives a β-hydroxycarboxylic acid.
- Deng, Min-Zhi,Lu, Ding-An,Xu, Wei-Hua
-
p. 1478 - 1479
(2007/10/02)
-