Product binding and role of the C-terminal region in Class I D-fructose 1, 6-bisphosphate aldolase

Abstract

The structure of fructose 1,6-bisphosphate aldolase shows three distinct modes of product binding that are correlated to the disposition of the C-terminal region and depicts a possible trajectory for product exchange. The structure also indicates binding preference for monobasic triose phosphates.

Expression, Purification, and Characterization of Natural Mutants of Human Aldolase B

“…Confirmation of the partial unfolding of the purified recombinant A337V aldolase B was recently provided by detailed circular dichroism measurements (8). The alanine residue is in proximity to Asn 334 on the preterminal ␣-helix, and the presence of the mutations in this segment will affect the conformation of the critical C-terminal tail segment of the enzyme and distort subunit integrity, thus also promoting tetramer dissociation (23). The incorrectly aligned C terminus postulated to result from the A337V residue causes a change in substrate specificity and affects affinity for the specific substrate of aldolase B, F-1-P.…”

“…The R303W residue is situated on the surface of the active site and participates in the binding of the carbon-1-phosphate of the substrates (23). 2 The catalytic mutant R303W had only 5% of the activity toward FBP and 3% of the activity toward F-1-P, when compared with wild-type.…”

“…The carbon-1-phosphate is an analogous moiety on F-1-P and DHAP and the common enamine intermediate binds to the Arg 303 residue (23). 2 The R303W residue could have an indirect effect on the C-terminal tyrosine.…”

“…The release of DHAP by the C terminus is a limiting step in the class 1 aldolase cleavage reaction (26). The C terminus in the rabbit liver aldolase binds to a triad of anionic surface residues adjacent to the active site that includes Arg 303 ; these residues serve as part of a docking site for the C-terminal tyrosine when substrate molecules are absent (23). When aldol substrate is present in the active site, the carbon-1-phosphate interacts with the Arg 303 residue and thus displaces the C terminus (23).…”

Expression, purification, crystallization and preliminary X-ray crystallographic analysis of fructose-1,6-bisphosphate aldolase fromEscherichia coli

“…The crystallographic study of FBPA I can be traced back to 1987 (Sygusch et al, 1987), since when more than 30 FBPA I structures have been deposited in the PDB. Several structures of FBPA I from eukaryotes and archaea (Hester et al, 1991;Lorentzen et al, 2003Lorentzen et al, , 2005Galkin et al, 2009;Blom & Sygusch, 1997) have been solved, but there is no information about the three-dimensional structures of bacterial FBPA I enzymes. Escherichia coli is one of the few organisms which contain both types of FBPA (Thomson et al, 1998).…”