Protein glycation and methylglyoxal metabolism in yeast: finding peptide needles in protein haystacks.
Metabolism, the set of all chemical transformations inside a living cell, comprises nonenzymatic processes that generate toxic products such as reactive oxygen species and 2-oxoaldehydes. Methylglyoxal, a highly reactive 2-oxoaldehyde by-product of glycolysis, is able to react irreversibly and nonenzymatically with proteins, forming methylglyoxal advanced glycation end-products, which alter protein structure, stability and function. Therefore, protein glycation may influence cell metabolism and its physiology in a way beyond what can be predicted based on the implicit codification used in systems biology. Genome-wide approaches and transcriptomics, two mainstays of systems biology, are powerless to tackle the problems caused by nonenzymatic reactions that are part of cell metabolism and biochemistry. The effects of methylglyoxal-derived protein glycation and the cell's response to this unspecific posttranslational modification were investigated in Saccharomyces cerevisiae as a model organism. Specific protein glycation phenotypes were identified using yeast null-mutants for methylglyoxal catabolism and the existence of specific protein glycation targets by peptide mass fingerprint was discovered. Enolase, the major target, endures a glycation-dependent activity loss caused by dissociation of the active dimer upon glycation at a specific arginine residue, identified using the hidden information of peptide mass fingerprint. Once glycation occurs, a cellular response involving heat shock proteins from the refolding chaperone pathway is elicited and Hsp26p is activated by glycation.
Gomes
Ricardo Anjos
RA
Departamento de Química e Bioquimica, Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Edifício, Lisboa, Portugal.
Vicente Miranda
Hugo
H
Sousa Silva
Marta
M
Graça
Gonçalo
G
Coelho
Ana Varela
AV
do Nascimento Ferreira
António Eduardo
AE
Cordeiro
Carlos
C
Freire
Ana Ponces
AP
D017127:Glycation End Products, Advanced; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011765:Pyruvaldehyde / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D049490:Systems Biology
D017127:Glycation End Products, Advanced; C499528:HSP26 protein, S cerevisiae; D006360:Heat-Shock Proteins; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D011765:Pyruvaldehyde