PDBsum entry 4jax

Transferase

PDB id: 4jax

Contents

Protein chains

(+ 0 more) 470 a.a.

Ligands

PO4 ×17

GOL ×8

Waters ×354

References listed in PDB file

Key reference

• Title: In vivo phosphorylation and in vitro autophosphorylation-Inactivation of kluyveromyces lactis hexokinase klhxk1.
• Authors: K.Kettner, E.B.Kuettner, A.Otto, H.Lilie, R.P.Golbik, N.Sträter, T.M.Kriegel.
• Ref.: Biochem Biophys Res Commun, 2013, 435, 313-318. [DOI no: 10.1016/j.bbrc.2013.03.121]
• PubMed id: 23583397

Abstract

The bifunctional hexokinase KlHxk1 is a key component of glucose-dependent signal transduction in Kluyveromyces lactis. KlHxk1 is phosphorylated in vivo and undergoes ATP-dependent autophosphorylation-inactivation in vitro. This study identifies serine-15 as the site of in vivo phosphorylation and serine-157 as the autophosphorylation-inactivation site. X-ray crystallography of the in vivo phosphorylated enzyme indicates the existence of a ring-shaped symmetrical homodimer carrying two phosphoserine-15 residues. In contrast, small-angle X-ray scattering and equilibrium sedimentation analyses reveal the existence of monomeric phosphoserine-15 KlHxk1 in solution. While phosphorylation at serine-15 and concomitant homodimer dissociation are likely to be involved in glucose signalling, mechanism and putative physiological significance of KlHxk1 inactivation by autophosphorylation at serine-157 remain to be established.