ABSTRACT
Copper is a vital metal cofactor in enzymes that are essential to myriad biological processes. Cellular acquisition of copper is primarily accomplished through the Ctr family of plasma membrane copper transport proteins. Model peptide studies indicate that the human Ctr1 N-terminus binds to Cu(II) with high affinity through an amino terminal Cu(II), Ni(II) (ATCUN) binding site. Unlike typical ATCUN-type peptides, the Ctr1 peptide facilitates the ascorbate-dependent reduction of Cu(II) bound in its ATCUN site by virtue of an adjacent HH (bis-His) sequence in the peptide. It is likely that the Cu(I) coordination environment influences the redox behavior of Cu bound to this peptide; however, the identity and coordination geometry of the Cu(I) site has not been elucidated from previous work. Here, we show data from NMR, XAS, and structural modeling that sheds light on the identity of the Cu(I) binding site of a Ctr1 model peptide. The Cu(I) site includes the same bis-His site identified in previous work to facilitate ascorbate-dependent Cu(II) reduction. The data presented here are consistent with a rational mechanism by which Ctr1 provides coordination environments that facilitate Cu(II) reduction prior to Cu(I) transport.
Subject(s)
Cation Transport Proteins/chemistry , Copper/chemistry , Histidine/chemistry , Methionine/chemistry , Peptides/chemistry , Binding Sites , Copper Transporter 1 , Humans , Models, Molecular , Molecular Structure , Quantum Theory , X-Ray Absorption SpectroscopyABSTRACT
This paper examines the aetiology of postpsychotic posttraumatic stress disorder (PP/PTSD) symptoms in a sample of participants who had been hospitalized following a psychotic episode. Forty two people hospitalized for a psychotic illness were interviewed during recovery to investigate whether a psychotic episode was associated with PTSD symptomatology. All participants found psychosis and hospitalization highly distressing. PP/PTSD symptoms were not associated with demographic factors, previous trauma, treatment, or insight. The PP/PTSD group reported more distress and intrusive memories associated with illness and treatment experiences and had higher scores for anxiety and dissociative symptoms. The development of PP/PTSD phenomenology was associated with the psychological distress of the experience.
