tailieunhanh - Báo cáo khoa học: Structural stability of the cofactor binding site in Escherichia coli serine hydroxymethyltransferase – the role of evolutionarily conserved hydrophobic contacts

According to their fold, pyridoxal 5¢-phosphate-dependent enzymes are grouped into five superfamilies. Fold Type I easily comprises the largest and most investigated group. The enzymes of this group have very similar 3D structures. | Structural stability of the cofactor binding site in Escherichia coli serine hydroxymethyltransferase - the role of evolutionarily conserved hydrophobic contacts Rita Florio1 Roberta Chiaraluce1 Valerio Consalvi1 Alessandro Paiardini1 Bruno Catacchio1 2 Francesco Bossa1 3 and Roberto Contestabile1 1 Dipartimento di Scienze Biochimiche A. Rossi Fanelli Sapienza University di Roma Italy 2 CNR Istituto di Biologia e Patologia Molecolari Sapienza Universita di Roma Italy 3 Centro di Eccellenza di Biologia e Medicina Molecolare BEMM Sapienza University di Roma Italy Keywords cofactor binding site conserved hydrophobic contacts pyridoxal phosphate serine hydroxymethyltransferase urea-induced denaturation Correspondence R. Contestabile Dipartimento di Scienze Biochimiche Sapienza University di Roma Piazzale Aldo Moro 5 00185 Roma Italy Fax 39 0649917566 Tel 39 0649917569 E-mail Website http bio_chem sito_biochimica EN Received 3 September 2009 revised 12 October 2009 accepted 16 October 2009 doi According to their fold pyridoxal 5 -phosphate-dependent enzymes are grouped into five superfamilies. Fold Type I easily comprises the largest and most investigated group. The enzymes of this group have very similar 3D structures. Remarkably the location of the cofactor in the active site between the two domains that form a single subunit is almost identical in all members of the group. Nonetheless Fold Type I enzymes show very little sequence identity raising the question as to which structural features determine the common fold. An important fold determinant appears to be the presence of three evolutionarily conserved clusters of hydrophobic contacts. A previous investigation which used Escherichia coli serine hydroxymethyltransferase a well characterized Fold Type I member demonstrated the involvement of one of these clusters in the stability of the quaternary structure. The present .