title: Stoichiometry of microtubule-associated protein (MAP2):tubulin and the localisation of the phosphorylation and cysteine residues along the MAP2 primary sequence.
abstract: The stoichiometry of the dimer between microtubule-associated protein 2 (MAP2) and tubulin has been determined by quantitative dodecylsulphate/polyacrylamide gel electrophoresis to be 1:12 mol X mol-1, a value equal to the number of phosphorylation sites that can be labelled in vitro. The distribution of these sites along the MAP2 primary sequence has been determined by cleaving pre-labelled MAP2 with either alpha-chymotrypsin or at the five cysteine residues with nitrothiocyanobenzoic acid. The phosphorylation sites lie in two clusters: ten within the known tubulin-binding domain at one end of the primary sequence, and a pair midway along the sequence. It is postulated that the tertiary structure of MAP2 is folded to bring all twelve sites into association with the twelve tubulin dimers.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001923:Brain Chemistry; D055598:Chemical Phenomena; D002621:Chemistry; D002645:Chickens; D002918:Chymotrypsin; D003545:Cysteine / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D008869:Microtubule-Associated Proteins; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D013861:Thiocyanates; D014404:Tubulin / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D011506:Proteins; D013861:Thiocyanates; D014404:Tubulin; D011494:Protein Kinases; D002918:Chymotrypsin; D003545:Cysteine; C008658:2-nitro-5-thiocyanobenzoic acid