Structural Aspects and Prediction of Calmodulin-Binding Proteins

Calmodulin (CaM) is an important intracellular protein that binds Ca²⁺ and functions as a critical second messenger involved in numerous biological activities through extensive interactions with proteins and peptides. CaM’s ability to adapt to binding targets with different structures is related to the flexible central helix separating the N- and C-terminal lobes, which allows for conformational changes between extended and collapsed forms of the protein. CaM-binding targets are most often identified using prediction algorithms that utilize sequence and structural data to predict regions of peptides and proteins that can interact with CaM. In this review, we provide an overview of different CaM-binding proteins, the motifs through which they interact with CaM, and shared properties that make them good binding partners for CaM. Additionally, we discuss the historical and current methods for predicting CaM binding, and the similarities and differences between these methods and their relative success at prediction. As new CaM-binding proteins are identified and classified, we will gain a broader understanding of the biological processes regulated through changes in Ca²⁺ concentration through interactions with CaM.     

Absence of detectable human herpesvirus 8 in the semen of human immunodeficiency virus-infected men without Kaposi's sarcoma

The prevalence of human herpesvirus 8 (HHV-8)/Kaposi's sarcoma (KS)-associated herpesvirus was investigated in the semen of 99 human immunodeficiency virus (HIV)-infected men (median CD4 cell count, 357/mm3) by use of a polymerase chain reaction (PCR) assay capable of detecting <10 copies of HHV-8 DNA. Of the subjects, 95 (96%) self-identified as men who have sex with men (MSM), and 3 had a history of clinical KS. Seminal cell specimens were negative for HHV-8 in 98 subjects. None of the 26 without KS (27.1% of 96 tested) who were seropositive for HHV-8 by IFA for latency-associated nuclear antigens had HHV-8 detected in their semen. The only subject with any evidence for seminal HHV-8 DNA was seropositive for HHV-8 and had active KS. HHV-8 was detected in 10 (10.4%) of 96 peripheral blood mononuclear cell specimens. The prevalence of HHV-8 DNA by PCR in semen of HIV-infected MSM without KS is low.     

The role of the American Board of Professional Psychology in professional mobility.

This article describes the role of certification by the American Board of Professional Psychology (ABPP) in easing the process by which psychologists move beyond their original jurisdictional boundaries to practice psychology. Meeting the requirements for licensure or certification in the various jurisdictions can be a difficult task because these requirements vary considerably from jurisdiction to jurisdiction. Other mechanisms that are available to facilitate this process include the Certificate of Professional Qualification in Psychology issued by the Association of State and Provincial Psychology Boards and certification by the National Register of Health Service Providers in Psychology. The ABPP certificate/diploma has been regarded by many state psychological associations and state boards of psychology as an appropriate way in which to recognize psychologists who are eligible for licensure/certification in a jurisdiction because of the examination requirements for board certification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remote sensing of Southern Ocean sea surface temperature: implications for marine biophysical models

Nineteen years of Advanced Very High Resolution Radiometer Multi-Channel Sea Surface Temperature (AVHRR MCSST) data were used to calculate monthly averages of sea surface temperatures (SSTs) for a large region of the Southern Ocean centred on Macquarie Island. Between October and February, the MCSST data were a reliable source of SSTs north of 60°S, but their quality (i.e. spatial and temporal density) was degraded severely at higher latitudes. Between April and August, the interpolated MCSST data were found to be unreliable in the study area, even at latitudes as low as 45°S. A specific problem has been identified to the west of Tasmania in the winter interpolated climatology which is likely an artefact of interpolation of sparse data. The poor coverage of valid MCSSTs during this time limits the data's application for many uses. Although the limitations of the MCSST data set are well recognised, the possibilities for ecological applications of these data remain largely unexplored and unquantified. The potential exists to maximize the information available from this and other similar data sets by determining the appropriate spatial and temporal scales at which they are best applied to biophysical models.     

Native valve infective endocarditis in elderly and younger adult patients: comparison of clinical features and outcomes with use of the Duke criteria and the Duke Endocarditis Database

The effect of age on the presentation and outcome of infective endocarditis (IE) is unclear. Many of the available data are based on analyses of mixed populations of patients including intravenous drug users or those with prosthetic valve endocarditis or native valve IE. We used the Duke criteria to compare the characteristics of 44 episodes of definite native valve IE in elderly patients (> 64 years old) with the characteristics of 64 similarly defined episodes of native valve IE in younger, nonintravenous-drug-using adult patients (> 29 years and < 60 years old). Our data suggest that the clinical presentation, characteristics, and outcome of native valve IE are similar for elderly patients and younger adult patients, although elderly patients were hospitalized an average of 12 days longer. Although we found that the occurrence of renal failure and cerebral embolism during an episode of IE was associated with higher rates of death (odds ratios, 4.8 and 4.0, respectively), age was not a significant contributor to mortality.     

Targeting peptide nucleic acid-protein conjugates to structural features within duplex DNA

URF13 is the product of a mitochondrial-encoded gene (T-urf13) found only in maize plants containing the Texas male-sterile cytoplasm (cms-T), and it is thought to be responsible for both cytoplasmic male sterility and the susceptibility of cms-T maize to the fungal pathogens Bipolaris maydis race T and Phyllosticata maydis. Mitochondria isolated from cms-T maize are uniquely sensitive to pathotoxins (T-toxin) produced by these fungi and to methomyl (a commercial insecticide). URF13 acts as a receptor that specifically binds T-toxin to produce hydrophilic pores in the inner mitochondrial membrane. When expressed in Escherichia coli cells, URF13 also forms hydrophilic pores in the plasma membrane if exposed to T-toxin or methomyl. Topological studies established that URF13 contains three membrane-spanning alpha-helices, two of which are amphipathic and can contribute to pore formation. Chemical cross-linking of URF13 was used to demonstrate the existence of URF13 oligomers in cms-T mitochondria and E. coli cells. The ability of the carboxylate-specific reagent, N,N'-dicyclohexycarbodiimide, to cross-link URF13 was used in conjunction with site-directed mutagenesis to establish that the URF13 tetramer has a central core consisting of a four-alpha-helical bundle which undergoes a conformational change after interaction with T-toxin or methomyl. Overall, the experimental evidence indicates that URF13 functions as a ligand-gated, pore-forming T-toxin receptor in cms-T mitochondria.     

Fourth International Conference on Durability of Building Materials and Components

RILEM Bulletin

Fourth International Conference on Durability of Building Materials and Components     

Human DDX3X Unwinds Japanese Encephalitis and Zika Viral 5′ Terminal Regions

Flavivirus genus includes many deadly viruses such as the Japanese encephalitis virus (JEV) and Zika virus (ZIKV). The 5′ terminal regions (TR) of flaviviruses interact with human proteins and such interactions are critical for viral replication. One of the human proteins identified to interact with the 5′ TR of JEV is the DEAD-box helicase, DDX3X. In this study, we in vitro transcribed the 5′ TR of JEV and demonstrated its direct interaction with recombinant DDX3X (K_d of 1.66 ± 0.21 µM) using microscale thermophoresis (MST). Due to the proposed structural similarities of 5′ and 3′ TRs of flaviviruses, we investigated if the ZIKV 5′ TR could also interact with human DDX3X. Our MST studies suggested that DDX3X recognizes ZIKV 5′ TR with a K_d of 7.05 ± 0.75 µM. Next, we performed helicase assays that suggested that the binding of DDX3X leads to the unwinding of JEV and ZIKV 5′ TRs. Overall, our data indicate, for the first time, that DDX3X can directly bind and unwind in vitro transcribed flaviviral TRs. In summary, our work indicates that DDX3X could be further explored as a therapeutic target to inhibit Flaviviral replication     

Chemical Synthesis and Biological Applications of O-GlcNAcylated Peptides and Proteins

All human cells use O-GlcNAc protein modifications (O-linked N-acetylglucosamine) to rapidly adapt to changing nutrient and stress conditions through signaling, epigenetic, and proteostasis mechanisms. A key challenge for biologists in defining precise roles for specific O-GlcNAc sites is synthetic access to homogenous isoforms of O-GlcNAc proteins, a result of the non-genetically templated, transient, and heterogeneous nature of O-GlcNAc modifications. Toward a solution, this review details the state of the art of two strategies for O-GlcNAc protein modification: advances in “bottom-up” O-GlcNAc peptide synthesis and direct “top-down” installation of O-GlcNAc on full proteins. We also describe key applications of synthetic O-GlcNAc peptide and protein tools as therapeutics, biophysical structure–function studies, biomarkers, and as disease mechanistic probes to advance translational O-GlcNAc biology.