ABSTRACT
The mechanism by which the contractile machinery of muscle is assembled and maintained is not well-understood. Members of the cysteine-rich protein (CRP) family have been implicated in these processes. Three vertebrate CRPs (CRP1-3) that exhibit developmentally regulated muscle-specific expression have been identified. All three proteins are associated with the actin cytoskeleton, and one has been shown to be required for striated muscle structure and function. The vertebrate CRPs identified to date display a similar molecular architecture; each protein is comprised of two tandemly arrayed LIM domains, protein-binding motifs found in a number of proteins with roles in cell differentiation. Each LIM domain coordinates two Zn(II) ions that are bound independently in CCHC (C=Cys, H=His) and CCCC modules. Here we describe the solution structure of chicken CRP1 determined by homonuclear and 1H-15N heteronuclear magnetic resonance spectroscopy. Comparison of the structures of the two LIM domains of CRP1 reveals a high degree of similarity in their tertiary folds. In addition, the two component LIM domains represent two completely independent folding units and exhibit no apparent interactions with each other. The structural independence and spatial separation of the two LIM domains of CRP1 are compatible with an adapter or linker role for the protein.
Subject(s)
Avian Proteins , Carrier Proteins/chemistry , Muscle, Smooth/cytology , Adaptor Proteins, Signal Transducing , Amino Acid Sequence , Animals , Carrier Proteins/physiology , Cell Differentiation , Chickens , Crystallography, X-Ray , LIM Domain Proteins , Models, Molecular , Molecular Sequence Data , Muscle, Smooth/chemistry , Nuclear Magnetic Resonance, Biomolecular , Protein Structure, Secondary , Protein Structure, Tertiary , Solutions , Zinc Fingers/physiologyABSTRACT
Chlamydia trachomatis serovar L1/440/LN possesses a 7498bp plasmid which was designated pLGV440. The plasmid was cloned at the BamH1 site of pAT153 into Escherichia coli and the recombinant plasmid was designated pCTL1. A detailed restriction endonuclease map of pCTL1 was constructed. A fragment of the chlamydial plasmid was shown to function as a promoter in E. coli when placed upstream of the lacZ gene. The entire plasmid was sequenced by the chain termination method. Open reading frames were identified from the resulting consensus sequence together with a candidate for the plasmid origin of replication consisting of four perfect tandem repeats of a 22bp sequence, an A:T rich sequence and an open reading frame which could generate a 34.8kdal product. The predicted polypeptide products of the open reading frames were compared by computer with all reported protein sequences. Homology of the predicted polypeptide product of an open reading frame to the E. coli dnaB protein and the analogous product of gene 12 of bacteriophage P22 is described.
Subject(s)
Chlamydia trachomatis/genetics , DNA Replication , Plasmids , Amino Acid Sequence , Base Sequence , Cloning, Molecular , DNA Restriction Enzymes , Escherichia coli/genetics , Genetic Vectors , Molecular Sequence Data , Promoter Regions, GeneticABSTRACT
Effects of learning names for random nonsense shapes prior to a probe-type serial-recall task were investigated in disabled readers. 33 10-yr.-old, right-handed boys were subjects in a 3 (reading groups) X 2 (training conditions) X 6 (serial positions) repeated-measures, split-plot level analysis of covariance design. No differences among reading groups on recall strength or primary recall were found, suggesting similar verbal skills. Deficiencies in verbal mediation did not appear to account for the reading disability of these subgroups.
