Carboxypeptidase A: Difference between revisions

1CPX’s most interesting distinction from other CPA proteins is that its crystallographic data revealed a different conformation of the Tyr248 residue (CITE main article)(SHOW PICTURE). Previous literature has suggested that the conserved Tyr residue amongst CPA proteins has been involved in an induced fit mechanism (BLUE LINK) because it typically has been found pointing outward toward solution (GREEN LINK) when a substrate is not bound to the enzyme (see 3CPA (BLUE LINK)) (CITE main article). However, 1CPX's crystallographic data shows Tyr248 pointing toward the active site (GREEN LINK) without a substrate bound. Therefore, this denies the previously proposed induced fit mechanism for CPA proteins and suggests that Tyr 248 is a ligand to the catalytic Zn (SUPERSCRIPT) in 1CPX (CITE MAIN ARTICLE). Moreover, this data supports that this is the native conformation of Tyr248 in solution because none of the residues in the protein’s active site interact in the crystallographic packing (main article, 59, 60). Not only does Tyr248 point toward the active site, but in doing so, Tyr248 caps the hydrophobic binding pocket (GREEN LINK) with its interactions with Ile247 and a hydrogen bond (cite).