Structural Studies of the BAM Complex, OmpU Outer Membrane Protein and Lipoprotein N-acyl Transferase in Gram-negative Bacteria PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Structural Studies of the BAM Complex, OmpU Outer Membrane Protein and Lipoprotein N-acyl Transferase in Gram-negative Bacteria PDF full book. Access full book title Structural Studies of the BAM Complex, OmpU Outer Membrane Protein and Lipoprotein N-acyl Transferase in Gram-negative Bacteria by Huanyu Li. Download full books in PDF and EPUB format.
Author: Huanyu Li
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Huanyu Li
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Susan Buchanan
Publisher: Humana
ISBN: 9781493928705
Category : Science
Languages : en
Pages : 0
Get Book Here
Book Description
This volume is comprised of a collection of experimental protocols for common techniques and strategies used to study the biogenesis of b-barrel outer membrane proteins in Gram-negative bacteria. The BAM Complex: Methods and Protocols guides readers through methods on the function of the BAM complex, the roles played by each of the individual components, the expression and purification of the components, crystallization and structure determination of the components, and how the individual Bam components may assemble into a functional complex. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, The BAM Complex: Methods and Protocols will serve as an invaluable reference for those interested in studying the BAM complex.
![Structural Analysis of the Escherichia Coli [beta]-barrel Assembly Machinery Complex PDF](https://books.google.com/books/content/images/frontcover/HZN-0AEACAAJ?fife=w80-h100)
Author: Kelly (Hyojin) Kim
Publisher:
ISBN:
Category : Escherichia coli
Languages : en
Pages : 0
Get Book Here
Book Description
The outer membrane (OM) is a unique structural feature of Gram-negative bacteria. Residing within the outer membrane are [beta]-barrel outer membrane proteins (OMPs) that serve many important cellular functions. As proper folding and assembly of these proteins are crucial for cell viability, Gram-negative bacteria possess a specialized proteinaceous machine, known as the BAM ([beta]-barrel assembly machinery) complex, to catalyze the folding and membrane insertion of OMPs. In Escherichia coli, the BAM complex consists of five proteins: one [beta]-barrel membrane protein -- BamA, and four lipoproteins -- BamB, BamC, BamD, and BamE. The roles of the individual components and how they are arranged into the BAM complex to function together is not yet clearly understood. During the course of this thesis project, I determined the structures of E. coli BamB, BamC, BamE and the BamCD subcomplex. Analysis of the conserved residues and the molecular surface properties of these solved structures helped to identify potential protein-protein interaction sites on each lipoprotein. For example, BamC has two 'helix-grip' domains that are ideally shaped to accommodate [alpha]-helices. BamB, on the other hand, has a [beta]-propeller fold that could potentially interact with BamA or substrates via [beta]-augmentation, a mode of interaction in which a pre-existing [beta]-sheet is augmented by an addition of a [beta]-strand of another protein. Comparing the solved structures with their structural homologs with known functions has also provided important clues about the functional roles of each lipoprotein. BamD structure, for example, closely resembles the binding pocket of a peroxisomal targeting signal receptor PEX5, suggesting a similar substrate recognition function for BamD. Interestingly, our BamCD complex structure shows that the putative substrate binding pocket of BamD is bound and blocked by the conserved unstructured N-terminal region of BamC. This suggests a possibility that BamC may have a regulatory function. The structural and interaction data acquired from this thesis project contributes to a better understanding of the BAM complex structure and provides a platform for future research driven by structure-based hypotheses.
Author: Khatira Anwari
Publisher:
ISBN:
Category :
Languages : en
Pages : 286
Get Book Here
Book Description
The outer membrane of Gram-negative bacteria is a compartment that houses many proteins involved in basic physiological functions, virulence and multi-drug resistance, and is therefore important for cell survival. Most proteins in the outer membrane adopt a [beta]-barrel conformation, and require the [beta]-barrel assembly machinery (BAM) for integration into the outer membrane. The BAM complex is a multi-subunit protein complex present in the outer membrane of all Gram-negative bacteria. It comprises of a core [beta]-barrel protein, BamA and associated lipoproteins that collectively participate in the folding and insertion of [beta]-barrel proteins. BamA has functional homologues in eukaryotes that form the SAM complex in mitochondria for insertion and assembly of [beta]-barrel proteins into the mitochondrial outer membranes. Previous work by other groups in the field has used N. meningitidis ([beta]-proteobacteria) and E. coli (y-proteobacteria) to study the function of BamA and the BAM complex. In this comparative study, we will use Caulobacter crescentus as a model [alpha]-proteobacterium to learn about differences and similarities in the BAM complexes across the three different classes of proteobacteria. The combined use of bioinformatics and biochemical experiments in C. crescentus have shown some key differences with the absence of the BamC partner lipoprotein and the presence of a novel OmpA-like protein as well as two other uncharacterized lipoprotein partners for BamA. In Chapter 2, we perform a comparative analysis of BamA and the BamA-like protein (Omp68) in C. crescentus. The Omp85 superfamily contains BamA, Omp68 and TpsB proteins and using bioinformatics analysis, we proposed that Omp68 is an evolutionary intermediate of BamA and TpsB proteins. We first established a method for preparing outer membranes from C. crescentus and demonstrated that like BamA, Omp68 forms an oligomeric complex in the outer membrane although it has characteristics that could classify it as a TpsB protein. The unusual nature of Omp68 is discussed and its possible functions. A method for effective purification of the BAM complex from outer membranes was also established for identification and analysis of the different components of the complex.In Chapter 3, we demonstrate that the BAM complex possesses modular characteristics and contains BamA and six outer membrane lipoproteins in the [alpha]-proteobacterium, C. crescentus. In addition to the three known lipoproteins (BamB, BamD and BamE), we identify three other subunits (Pal, BamF and BamG) of which only Pal is essential. We propose that Pal is a protein that anchors the BAM complex to the peptidoglycan layer and promotes proximity to the inner membrane Sec machinery for efficient outer membrane protein assembly. We also show BamF is a genuine component of the BAM complex and a potential homologue of the BamC protein found in all other proteobacteria. Both BamF and BamC contain a conserved motif that is possibly important for docking onto the BAM complex.In Chapter 4, we focus on biochemical and structural characterisations of BamD from C. crescentus. We show BamD is an outer membrane lipoprotein that forms the halo module of the BAM complex. We also demonstrate BamD contains TPR motifs that are essential for functioning of the BAM complex and that protrude into the periplasm for protein-protein interactions. Further experiments involved extensive optimisations of heterologous expression of BamD and purification with the aim of progressing to crystallisation trials. We were able to generate purified folded BamD that will be used for future experiments.
