Transient local secondary structure in the intrinsically disordered C-term of the Albino3 insertase.

Albino3 (Alb3) is an integral membrane protein fundamental to the targeting and insertion of light-harvesting complex (LHC) proteins into the thylakoid membrane. Alb3 contains a stroma-exposed C-terminus (Alb3-Cterm) that is responsible for binding the LHC-loaded transit complex before LHC membrane insertion. Alb3-Cterm has been reported to be intrinsically disordered, but precise mechanistic details underlying how it recognizes and binds to the transit complex are lacking, and the functional roles of its four different motifs have been debated.

Domain Organization in the 54-kDa Subunit of the Chloroplast Signal Recognition Particle.

Chloroplast signal recognition particle (cpSRP) is a heterodimer composed of an evolutionarily conserved 54-kDa GTPase (cpSRP54) and a unique 43-kDa subunit (cpSRP43) responsible for delivering light-harvesting chlorophyll binding protein to the thylakoid membrane. While a nearly complete three-dimensional structure of cpSRP43 has been determined, no high-resolution structure is yet available for cpSRP54. In this study, we developed and examined an in silico three-dimensional model of the structure of cpSRP54 by homology modeling using cytosolic homologs.

Regulation of Structural Dynamics within a Signal Recognition Particle Promotes Binding of Protein Targeting Substrates.

Protein targeting is critical in all living organisms and involves a signal recognition particle (SRP), an SRP receptor, and a translocase. In co-translational targeting, interactions among these proteins are mediated by the ribosome. In chloroplasts, the light-harvesting chlorophyll-binding protein (LHCP) in the thylakoid membrane is targeted post-translationally without a ribosome.

First human study of a chimeric anti-methamphetamine monoclonal antibody in healthy volunteers.

This first-in-human study examined the safety and pharmacokinetics of ch-mAb7F9, an anti-methamphetamine monoclonal antibody, in healthy volunteers. Single, escalating doses of ch-mAb7F9 over the range of 0.2 to 20 mg/kg were administered to 42 subjects who were followed for 147 d.

Preclinical characterization of an anti-methamphetamine monoclonal antibody for human use.

Ch-mAb7F9, a human-mouse chimeric monoclonal antibody (mAb) designed to bind (+)-methamphetamine (METH) with high affinity and specificity, was produced as a treatment medication for METH abuse. In these studies, we present the preclinical characterization that provided predictive evidence that ch-mAb7F9 may be safe and effective in humans. In vitro ligand binding studies showed that ch-mAb7F9 is specific for and only binds its target ligands (METH, (+)-amphetamine, and 3,4-methylenedioxy-N-methylamphetamine) with high affinity.

Radiation-induced galectin-1 by endothelial cells: a promising molecular target for preferential drug delivery to the tumor vasculature.

The present study reports on a new strategy for selective, radiation therapy-amplified drug delivery using an antiangiogenic 33-a.a., tumor vasculature-targeting ligand, anginex, to improve the therapeutic ratio for strategies developed against solid tumors.

A dynamic cpSRP43-Albino3 interaction mediates translocase regulation of chloroplast signal recognition particle (cpSRP)-targeting components.

The chloroplast signal recognition particle (cpSRP) and its receptor, chloroplast FtsY (cpFtsY), form an essential complex with the translocase Albino3 (Alb3) during post-translational targeting of light-harvesting chlorophyll-binding proteins (LHCPs). Here, we describe a combination of studies that explore the binding interface and functional role of a previously identified cpSRP43-Alb3 interaction. Using recombinant proteins corresponding to the C terminus of Alb3 (Alb3-Cterm) and various domains of cpSRP43, we identify the ankyrin repeat region of cpSRP43 as the domain primarily responsible for the interaction with Alb3-Cterm.

The membrane-binding motif of the chloroplast signal recognition particle receptor (cpFtsY) regulates GTPase activity.

The chloroplast signal recognition particle (cpSRP) and its receptor (cpFtsY) function in thylakoid biogenesis to target integral membrane proteins to thylakoids. Unlike cytosolic SRP receptors in eukaryotes, cpFtsY partitions between thylakoid membranes and the soluble stroma. Based on sequence alignments, a membrane-binding motif identified in Escherichia coli FtsY appears to be conserved in cpFtsY, yet whether the proposed motif is responsible for the membrane-binding function of cpFtsY has yet to be shown experimentally.

Monoclonal antibody form and function: manufacturing the right antibodies for treating drug abuse.

Drug abuse continues to be a major national and worldwide problem, and effective treatment strategies are badly needed. Antibodies are promising therapies for the treatment of medical problems caused by drug abuse, with several candidates in preclinical and early clinical trials. Monoclonal antibodies can be designed that have customized affinity and specificity against drugs of abuse, and because antibodies can be designed in various forms, in vivo pharmacokinetic characteristics can be tailored to suit specific clinical applications (eg, long-acting for relapse prevention, or short-acting for overdose).

Deletion of the chloroplast-localized Thylakoid formation1 gene product in Arabidopsis leads to deficient thylakoid formation and variegated leaves.

Development of thylakoid membranes depends upon the transport of membrane vesicles from the chloroplast inner envelope and subsequent fusion of vesicles within the interior of the plastid. The Arabidopsis (Arabidopsis thaliana) Thylakoid formation1 (Thf1) gene product is shown here to control an important step required for the normal organization of these vesicles into mature thylakoid stacks and ultimately for leaf development. The Arabidopsis Thf1 gene encodes an imported chloroplast protein, as shown by in vitro import and localization of a Thf1-green fluorescent protein fusion product in transgenic plants.

Regulation of the GTPase cycle in post-translational signal recognition particle-based protein targeting involves cpSRP43.

The chloroplast signal recognition particle consists of a conserved 54-kDa GTPase and a novel 43-kDa chromodomain protein (cpSRP43) that together bind light-harvesting chlorophyll a/b-binding protein (LHCP) to form a soluble targeting complex that is subsequently directed to the thylakoid membrane. Homology-based modeling of cpSRP43 indicates the presence of two previously identified chromodomains along with a third N-terminal chromodomain. Chromodomain deletion constructs were used to examine the role of each chromodomain in mediating distinct steps in the LHCP localization mechanism.