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Journal Issue - Volume 16 Issue 5 (May 2007)

Abstract We have developed a bacterial two‐hybrid system for the detection of interacting proteins that capitalizes on the folding quality control mechanism of the Twin Arginine Transporter (Tat) pathway. The Tat export pathway is responsible for the membrane translocation of folded proteins, including proteins consisting of more than one polypeptide, only one of which contains a signal peptide (“hitchhiker export”). Here, one...

Abstract The bacterial flagellum is a highly complex prokaryotic organelle. It is the motor that drives bacterial motility, and despite the large amount of energy required to make and operate flagella, motile organisms have a strong adaptive advantage. Flagellar biogenesis is both complex and highly coordinated and it typically involves at least three two‐component systems. Part of the flagellum is a type III secretion system, and...

Abstract Previous laser flash photolysis investigations between 100 and 300 K have shown that the kinetics of CO rebinding with cytochrome P450cam(camphor) consist of up to four different processes revealing a complex internal dynamics after ligand dissociation. In the present work, molecular dynamics simulations were undertaken on the ternary complex P450cam(cam)(CO) to explore the CO migration pathways, monitor the internal cavities of the...

Abstract Pathogenic members of the flavivirus family, including West Nile Virus (WNV) and Dengue Virus (DV), are growing global threats for which there are no specific treatments. The two‐component flaviviral enzyme NS2B‐NS3 cleaves the viral polyprotein precursor within the host cell, a process that is required for viral replication. Here, we report the crystal structure of WNV NS2B‐NS3pro both in a substrate‐free form and in...

  • Solution structure of human sorting nexin 22

  • Jikui Song, Kate Qin Zhao, Carrie L. Loushin Newman, Dmitriy A. Vinarov, John L. Markley
  • Published in Wiley Interscience on Jan 02, 2009
  • DOI: 10.1110/ps.072752407 (p 807-814)

Abstract The sorting nexins (SNXs) constitute a large group of PX domain‐containing proteins that play critical roles in protein trafficking. We report here the solution structure of human sorting nexin 22 (SNX22). Although SNX22 has <30% sequence identity with any PX domain protein of known structure, it was found to contain the α/β fold and compact structural core characteristic of PX domains. Analysis of the backbone dynamics...

Abstract Amyloid fibril depositions are associated with many neurodegenerative diseases as well as amyloidosis. The detailed molecular mechanism of fibrillation is still far from complete understanding. In our previous study of in vitro fibrillation of hen egg white lysozyme, an irreversible partially unfolded intermediate was characterized. A similarity of unfolding kinetics found for the secondary and tertiary structure of...

Abstract Plasminogen activator inhibitor‐1 (PAI‐1), a member of the serine protease inhibitor (serpin) protein family, is unique among the serpins in its conformational lability. This lability allows spontaneous conversion of the active form to a more stable, latent conformation under physiological conditions. In other serpins, polymerization, rather than latency transition, is induced under pathological conditions or upon heat...

Abstract Small proteins are generally observed to fold in an apparent two‐state manner. Recently, however, more sensitive techniques have demonstrated that even seemingly single‐domain proteins are actually made up of smaller subdomains. T4 lysozyme is one such protein. We explored the relative autonomy of its two individual subdomains and their contribution to the overall stability of T4 lysozyme by examining a circular permutation...

Abstract Intermediates along a protein's folding pathway can play an important role in its biology. Previous kinetics studies have revealed an early folding intermediate for T4 lysozyme, a small, well‐characterized protein composed of an N‐terminal and a C‐terminal subdomain. Pulse‐labeling hydrogen exchange studies suggest that residues from both subdomains contribute to the structure of this intermediate. On the other hand,...

Abstract Many stably folded proteins are proposed to contain long, unstructured loops. A series of hybrid proteins (EbE1–4) containing the folded scaffold of photosystem I accessory protein E (PsaE), an SH3‐like protein, and the 40‐residue heme‐binding loop of cytochrome b5 was created to inspect the dependence of thermodynamic and kinetic parameters on the residues at the interface of folded and flexible regions. Compared to the...

Abstract MAP kinase phosphatases (MKPs) have crucial roles in regulating the signaling activity of MAP kinases and are potential targets for drug discovery against human diseases. These enzymes contain a catalytic domain (CD) as well as a binding domain (BD) that help recognize the target MAP kinase. We report here the crystal structures at up to 2.2 Å resolution of the BD and CD of human MKP5 and compare them to the known...

Abstract Desosamine is a 3‐(dimethylamino)‐3,4,6‐trideoxyhexose found in certain macrolide antibiotics such as the commonly prescribed erythromycin. Six enzymes are required for its biosynthesis in Streptomyces venezuelae. The focus of this article is DesV, which catalyzes the PLP‐dependent replacement of a 3‐keto group with an amino functionality in the fifth step of the pathway. For this study the three‐dimensional structures of both the...

Abstract Lasofoxifene is a new and potent selective estrogen receptor modulator (SERM). The structural basis of its interaction with the estrogen receptor has been investigated by crystallographic analysis of its complex with the ligand‐binding domain of estrogen receptor α at a resolution of 2.0 Å. As with other SERMs, lasofoxifene diverts the receptor from its agonist‐bound conformation by displacing the C‐terminal AF‐2 helix into...

Abstract Fibrillar inclusions are a characteristic feature of the neuropathology found in the α‐synucleinopathies such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Familial forms of α‐synucleinopathies have also been linked with missense mutations or gene multiplications that result in higher protein expression levels. In order to form these fibrils, the protein, α‐synuclein (α‐syn), must undergo a...

Abstract Protein arginine methylation often modulates protein–protein interactions. To isolate a sufficient quantity of proteins enriched in methyl arginine(s) from natural sources for biochemical studies is laborious and difficult. We describe here an expression system that produces recombinant proteins that are enriched in ω‐NG,NG‐asymmetry dimethylarginines. A yeast type I arginine methyltransferase gene (HMT1) is put on a plasmid under the...

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