Neuropsychiatric Disorders--protein Structure/activity S

National Institute Of Mental Health

Investigators

Linked publications & trials

Abstract

A goal of these studies is to better understand the molecular mechanisms underlying human nervous system development and function, as well as the pathogenesis of certain inherited brain disorders. Our studies have focused on the structural and active-site properties of proteins found in the nervous system including neurotrophic peptides/proteins, lysosomal hydrolases, and other proteins/peptides, which interact with excitable membranes, receptors and venom toxins. Proteins from human and animal tissues are purified by liquid chromatography (ion-exchange, gel permeation and affinity techniques), high performance liquid chromatography (HPLC) and electrophoretic separation. State-of-the-art micro sequencing analysis (gas-phase, liquid-phase and solid-phase), surface enhanced laser desorption ionization (SELDI) and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) are performed to characterize proteins. Both isoelectric-focusing and molecular weight determination of Pico mole amounts of proteins are carried out by capillary-zone electrophoresis. Peptide maps of both normal and mutant proteins are generated using chemical (mild acid, cyanogen bromide) and enzymatic (trypsin, AspN, V8 proteases) cleavage and analyzed by HPLC. Several novel scorpion venom neurotoxins, which interact with synaptosomal structures such as human calcium and potassium channels in excitable membranes, are being studied. We are also investigating the association of amyloid peptides with both high and low-density lipoproteins from cerebrospinal fluid in Alzheimer's disease. Our research emphasis is on studies that define post-translational processes not identifiable by DNA sequence analysis, e.g. carbohydrate attachment, protease cleavage, and phosphorylation that could be responsible for abnormal brain function. By a combination of methods described above, we have identified molecular forms of cystatin C in CSF, which is up regulated in pain and also found in the urine of people with varying degrees of renal dysfunction. We are evaluating several novel approaches for the identification of Bio Markers for psychiatric disorders as well as cancer. We have also discovered a simple rapid method for the recovery of peptides/proteins from tissue/cell samples that has been submitted as an employee invention report for assessment of patentability. Several new long chain potassium channel blocking peptides have been characterized from scorpion venom both directly from the protein and more recently by analysis of their cDNA sequence. Additionally, several novel defensin-like peptides have been characterized at both the peptide and cDNA level.