Differential effects on enzyme stability and kinetic parameters of mutants related to human triosephosphate isomerase deficiency

• Published in: Biochimica et biophysica acta Vol. 1862; no. 6; pp. 1401 - 1409
• Main Authors: Cabrera, Nallely, Torres-Larios, Alfredo, García-Torres, Itzhel, Enríquez-Flores, Sergio, Perez-Montfort, Ruy
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2018; Elsevier
• Subjects: Activity; Crystal structure; enzyme stability; Escherichia coli; genes; homozygosity; humans; mutants; mutation; Recombinant enzyme; Site directed mutagenesis; Stability; triose-phosphate isomerase; Triosephosphate isomerase deficiency; Activity; Recombinant enzyme; Stability; Site directed mutagenesis; Triosephosphate isomerase deficiency; Crystal structure
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2018.03.019

Human triosephosphate isomerase (TIM) deficiency is a very rare disease, but there are several mutations reported to be causing the illness. In this work, we produced nine recombinant human triosephosphate isomerases which have the mutations reported to produce TIM deficiency. These enzymes were characterized biophysically and biochemically to determine their kinetic and stability parameters, and also to substitute TIM activity in supporting the growth of an Escherichia coli strain lacking the tim gene. Our results allowed us to rate the deleteriousness of the human TIM mutants based on the type and severity of the alterations observed, to classify four “unknown severity mutants” with altered residues in positions 62, 72, 122 and 154 and to explain in structural terms the mutation V231M, the most affected mutant from the kinetic point of view and the only homozygous mutation reported besides E104D. •We studied nine recombinant mutant human TIMs associated with TIM deficiency.•The deleteriousness of the mutant TIMs could be rated based on the molecular alterations.•Four “unknown severity mutants” could be classified with this scheme.•A62D, the most disruptive mutant, was unable to support bacterial growth.•The 3-D structure of mutant V231M explains why patients suffer TIM deficiency.