Structural insight into G-protein chaperone-mediated maturation of a bacterial adenosylcobalamin-dependent mutase.

G-protein metallochaperones are essential for the proper maturation of numerous metalloenzymes. The G-protein chaperone MMAA in humans (MeaB in bacteria) uses GTP hydrolysis to facilitate the delivery of adenosylcobalamin (AdoCbl) to AdoCbl-dependent methylmalonyl-CoA mutase, an essential metabolic enzyme. This G-protein chaperone also facilitates the removal of damaged cobalamin (Cbl) for repair.

Structure of metallochaperone in complex with the cobalamin-binding domain of its target mutase provides insight into cofactor delivery.

G-protein metallochaperone MeaB in bacteria [methylmalonic aciduria type A (MMAA) in humans] is responsible for facilitating the delivery of adenosylcobalamin (AdoCbl) to methylmalonyl-CoA mutase (MCM), the only AdoCbl-dependent enzyme in humans. Genetic defects in the switch III region of MMAA lead to the genetic disorder methylmalonic aciduria in which the body is unable to process certain lipids. Here, we present a crystal structure of MeaB bound to a nonhydrolyzable guanosine triphosphate (GTP) analog guanosine-5'-[(β,γ)-methyleno]triphosphate (GMPPCP) with the Cbl-binding domain of its target mutase enzyme (MCM).

Rationally Designed Base Editors for Precise Editing of the Sickle Cell Disease Mutation.

Base editors are fusions of a deaminase and CRISPR-Cas ribonucleoprotein that allow programmable installment of transition mutations without double-strand DNA break intermediates. The breadth of potential base editing targets is frequently limited by the requirement of a suitably positioned Cas9 protospacer adjacent motif. To address this, we used structures of Cas9 and TadA to design a set of inlaid base editors (IBEs), in which deaminase domains are internal to Cas9.

Cytosine base editors with minimized unguided DNA and RNA off-target events and high on-target activity.

Cytosine base editors (CBEs) enable efficient, programmable reversion of T•A to C•G point mutations in the human genome. Recently, cytosine base editors with rAPOBEC1 were reported to induce unguided cytosine deamination in genomic DNA and cellular RNA. Here we report eight next-generation CBEs (BE4 with either RrA3F [wt, F130L], AmAPOBEC1, SsAPOBEC3B [wt, R54Q], or PpAPOBEC1 [wt, H122A, R33A]) that display comparable DNA on-target editing frequencies, whilst eliciting a 12- to 69-fold reduction in C-to-U edits in the transcriptome, and up to a 45-fold overall reduction in unguided off-target DNA deamination relative to BE4 containing rAPOBEC1.

Directed evolution of adenine base editors with increased activity and therapeutic application.

The foundational adenine base editors (for example, ABE7.10) enable programmable A•T to G•C point mutations but editing efficiencies can be low at challenging loci in primary human cells. Here we further evolve ABE7.

Author Correction: Phenotypes associated with genes encoding drug targets are predictive of clinical trial side effects.

In the original version of this article, there were errors in the labelling of the colours in the key of Figure 2, whereby the labeling of the third and fourth of the four colours was reversed. This has been corrected in both the PDF and HTML versions of the article.

Phenotypes associated with genes encoding drug targets are predictive of clinical trial side effects.

Only a small fraction of early drug programs progress to the market, due to safety and efficacy failures, despite extensive efforts to predict safety. Characterizing the effect of natural variation in the genes encoding drug targets should present a powerful approach to predict side effects arising from drugging particular proteins. In this retrospective analysis, we report a correlation between the organ systems affected by genetic variation in drug targets and the organ systems in which side effects are observed.

Isonitrile Formation by a Non-Heme Iron(II)-Dependent Oxidase/Decarboxylase.

The electron-rich isonitrile is an important functionality in bioactive natural products, but its biosynthesis has been restricted to the IsnA family of isonitrile synthases. We herein provide the first structural and biochemical evidence of an alternative mechanism for isonitrile formation. ScoE, a putative non-heme iron(II)-dependent enzyme from Streptomyces coeruleorubidus, was shown to catalyze the conversion of (R)-3-((carboxymethyl)amino)butanoic acid to (R)-3-isocyanobutanoic acid through an oxidative decarboxylation mechanism.

Structural basis for methylphosphonate biosynthesis.

Methylphosphonate synthase (MPnS) produces methylphosphonate, a metabolic precursor to methane in the upper ocean. Here, we determine a 2.35-angstrom resolution structure of MPnS and discover that it has an unusual 2-histidine-1-glutamine iron-coordinating triad.

Sikhs in Minnesota: Dental Care Access, Ethnicity, and Acculturation.

To explore the dental care experiences of one of Minnesota's ethnic communities, the authors conducted pilot study among members of Sikh temple. The Sikhs, a religious group from the Punjab region of India, number roughly 1,500-2,000 individuals in the Twin Cities. Forty-seven adults from the Bloomington, Minnesot temple completed the survey, which was administered during interviews with one of the authors, himself a Sikh.

Structural Basis for Substrate Specificity in Adenosylcobalamin-dependent Isobutyryl-CoA Mutase and Related Acyl-CoA Mutases.

Acyl-CoA mutases are a growing class of adenosylcobalamin-dependent radical enzymes that perform challenging carbon skeleton rearrangements in primary and secondary metabolism. Members of this class of enzymes must precisely control substrate positioning to prevent oxidative interception of radical intermediates during catalysis. Our understanding of substrate specificity and catalysis in acyl-CoA mutases, however, is incomplete.

Dental therapy: evolving in Minnesota's safety net.

Objectives: We identified Minnesota's initial dental therapy employers and surveyed dental safety net providers' perceptions of dental therapy.

Methods: In July 2011, we surveyed 32 Minnesota dental safety net providers to assess their prospective views on dental therapy employment options. In October 2013, we used an employment scan to reveal characteristics of the early adopters of dental therapy.

Beginning the socialization to a new workforce model: dental students' preliminary knowledge of and attitudes about the role of the dental therapist.

The purpose of the study reported here was to assess first- and second-year dental students' knowledge of and attitudes about the role of the dental therapist in the oral health care delivery system. The results of this study are informing the continued development and implementation of a new dental workforce training model at the University of Minnesota. Dental students at the university (Classes of 2012 and 2013) were surveyed in 2009, with follow-up surveys planned for the subsequent five years.

Dental hygiene workforce issues: a Minnesota study.

Purpose: This study was designed to explore the prevalence and reasons for withdrawal from the dental hygiene workforce. The study also assessed the reasons for maintaining an active license after withdrawal, and the factors that might entice an individual to return to the dental hygiene workforce.

Methods: A random sample was selected of dental hygienists licensed in Minnesota from the November 2003 State Board of Dentistry's dental hygiene licensing file.

Self-reported toothache experience in an adult population in Benin City, Edo State, Nigeria.

Purpose: This pilot study was conducted to estimate the prevalence of self-reported toothache, bleeding gums and oral ulcer experiences, reasons for dental visits and associated sociodemographic factors among adults living in Benin City, Edo State, Nigeria.

Materials And Methods: This cross-sectional study was based on a convenience sample in an urban setting. Out of the 540 persons surveyed, 508 had complete usable information, 48% males and 52% females, and aged 18 - 54 years.

Self-reported dental visits among adults in Benin City, Nigeria.

Objective: To identify patterns and predictive factors independently associated with self-reported dental visits of adults resident in Benin City, Edo State, Nigeria.

Methods: A cross-sectional study of 358 adults aged 18-64 years using a closed ended, oral health questionnaire administered by trained interviewers to assess sociodemographic information and factors associated with oral healthcare utilisation.

Results: 26% of adults reported having visited a dentist within the previous 12 months, 22% within 12-36 months, 30% over 36 months previously, and 22% had never been to a dentist.