Crystallization and preliminary X-ray analysis of dmpFG-encoded 4-hydroxy-2-ketovalerate aldolase-aldehyde dehydrogenase (acylating) from Pseudomonassp strain CF600

The final two steps of the meta-cleavage pathway for catechol degradation i n Pseudomonas sp. strain CF600 involve the conversion of 4-hydroxy-2-ketova lerate to pyruvate and acetyl coenzyme A by the enzymes 4-hydroxy-2-ketoval erate aldolase and NAD(+)-dependent acylating aldehyde dehydrogenase. Bioch emical studies indicate that these two enzymes comprise a bifunctional hete rodimer (DmpFG, molecular mass 71 kDa) and suggest that the product of the aldolase reaction is transferred to the dehydrogenase active site via a cha nneling mechanism. Crystals of the DmpFG complex grow in multiple fan-like clusters of thin plates by the hanging-drop method and are improved by stre ak-seeding. The crystals belong to the orthorhombic space group P2(1)2(1)2( 1), with unit-cell parameters a = 102.0, b = 140.7, c = 191.3 Angstrom, and diffract to 2.1 Angstrom resolution. The asymmetric unit contains four Dmp FG heterodimers. Heavy-atom derivative screening identified three isomorpho us derivatives.