Dataset Information

Diagnostic cross-linking of paired cysteine pairs demonstrates homologous structures for two chemoreceptor domains with low sequence identity.

ABSTRACT: Hundreds of bacterial chemoreceptors from many species have periplasmic, ligand-recognition domains of approximately the same size, but little or no sequence identity. The only structure determined is for the periplasmic domain of chemoreceptor Tar from Salmonella and Escherichia coli. Do sequence-divergent but similarly sized chemoreceptor periplasmic domains have related structures? We addressed this issue for the periplasmic domain of chemoreceptor Trg(E) from E. coli, which has a low level of sequence similarity to Tar, by combining homology modeling and diagnostic cross-linking between pairs of introduced cysteines. A homology model of the Trg(E) domain was created using the homodimeric, four-helix bundle structure of the Tar(S) domain from Salmonella. In this model, we chose four pairs of positions at which introduced cysteines would be sufficiently close to form disulfides across each of four different helical interfaces. For each pair we chose a second pair, in which one cysteine of the original pair was shifted by one position around the helix and thus would be less favorably placed for disulfide formation. We created genes coding for proteins containing four such pairs of cysteine pairs and investigated disulfide formation in vivo as well as functional consequences of the substitutions and disulfides between neighboring helices. Results of the experimental tests provided strong support for the accuracy of the model, indicating that the Trg(E) periplasmic domain is very similar to the Tar(S) domain. Diagnostic cross-linking of paired pairs of introduced cysteines could be applied generally as a stringent test of homology models.

SUBMITTER: Lai WC

PROVIDER: S-EPMC2242362 | biostudies-literature | 2006 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Diagnostic cross-linking of paired cysteine pairs demonstrates homologous structures for two chemoreceptor domains with low sequence identity.

Lai Wing-Cheung WC Peach Megan L ML Lybrand Terry P TP Hazelbauer Gerald L GL

Protein science : a publication of the Protein Society 20051201 1

Hundreds of bacterial chemoreceptors from many species have periplasmic, ligand-recognition domains of approximately the same size, but little or no sequence identity. The only structure determined is for the periplasmic domain of chemoreceptor Tar from Salmonella and Escherichia coli. Do sequence-divergent but similarly sized chemoreceptor periplasmic domains have related structures? We addressed this issue for the periplasmic domain of chemoreceptor Trg(E) from E. coli, which has a low level o ...[more]

PMID: 16322572

Similar Datasets

Project description:The narrative and dual-cycle approach conceptualize and operationalize adolescents' identity formation in different ways. While the narrative approach focuses on the construction of an autobiographical life story, the dual-cycle approach focuses on the formation of identity commitments. Although these approaches have different emphases, they are conceptually complementary. Yet, their empirical links and distinctions have only scarcely been investigated. Empirical knowledge on these links in adolescence and across time has been especially lacking. In the present research, it was therefore examined whether key characteristics of adolescents' narration (autobiographical reasoning and agency) were concurrently and prospectively related to engagement in the dual-cycle processes of commitment making, identification with commitment, exploration in breadth, exploration in depth, and ruminative exploration. The findings from a cross-sectional sample of 1,580 Dutch adolescents (Mage = 14.7 years, 56% female) demonstrated that autobiographical reasoning was significantly positively associated with the commitment and more adaptive exploration processes (i.e., in breadth and in depth). In addition, agency was significantly positively associated with the commitment processes and exploration in depth. Yet, these associations between the narrative characteristics and dual-cycle processes were only weak. Subsequently, the findings from a two-year longitudinal subsample (n = 242, Mage = 14.7 years, 62% female) indicated that on average commitment strength remained stable but exploration increased across middle adolescence. A stronger increase in identification with commitment and adaptive exploration (i.e., in breadth and in depth) was predicted by a higher degree of agency in adolescents' narratives. Overall, these findings indicate that both approaches to identity formation are associated, but the small size of these associations suggests that they predominantly capture unique aspects of identity formation. Both approaches could thus complement and inform each other.

Dataset Information

Diagnostic cross-linking of paired cysteine pairs demonstrates homologous structures for two chemoreceptor domains with low sequence identity.

Publications

Diagnostic cross-linking of paired cysteine pairs demonstrates homologous structures for two chemoreceptor domains with low sequence identity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets