Identification of residues involved in allosteric signal transmission from amino acid binding site of pyruvate kinase muscle isoform 2

• Published in: PloS one 2023-03, Vol.18 (3), p.e0282508
• Main Authors: Nandi, Suparno, Dey, Mishtu
• Format: Article
• Language: English
• Subjects: Adenosine; Allosteric enzymes; Allosteric properties; Amino acids; Amino Acids - metabolism; Binding sites; Biology and Life Sciences; Cancer; Catalytic Domain; Cell division; Chains; Enzymes; Glycolysis; Health aspects; Humans; Kinases; MATERIALS SCIENCE; Medicine and Health Sciences; Muscles; Mutation; Phosphorylation; Physical Sciences; Plasmids; Protein Isoforms - metabolism; Pyruvate kinase; Pyruvate Kinase - chemistry; Pyruvate Kinase - metabolism; Pyruvic acid; Research and Analysis Methods; Residues; Science & Technology - Other Topics; Signal Transduction; Signal transmission; Substrates; Thyroid Hormone-Binding Proteins
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0282508

PKM2 is a rate-limiting enzyme in the glycolytic process and is involved in regulating tumor proliferation. Several amino acids (AAs) such as Asn, Asp, Val, and Cys have been shown to bind to the AA binding pocket of PKM2 and modulate its oligomeric state, substrate binding affinity, and activity. Although previous studies have attributed that the main chain and side chain of bound AAs are responsible for initiating signal to regulate PKM2, the signal transduction pathway remains elusive. To identify the residues involved in signal transfer process, N70 and N75 located at two ends of a β strand connecting the active site and AA binding pocket were altered. Biochemical studies of these variants with various AA ligands (Asn, Asp, Val, and Cys), illustrate that N70 and N75, along with β1 connecting these residues are part of the signal transduction pathway between the AA binding pocket and the active site. The results demonstrate that mutation of N70 to D prevents the transfer of the inhibitory signal mediated by Val and Cys, whereas N75 to L alteration blocks the activating signal initiated by Asn and Asp. Taken together, this study confirms that N70 is one of the residues responsible for transmitting the inhibitory signal and N75 is involved in the activation signal flow.