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Record W4256030778 · doi:10.1002/0470028637.met280

3‐Ketosteroid‐9α‐Hydroxylase

2004· other· en· W4256030778 on OpenAlexaff
Jenna K. Capyk, N.C.J. Strynadka, Lindsay D. Eltis

Bibliographic record

VenueHandbook of Metalloproteins · 2004
Typeother
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicSteroid Chemistry and Biochemistry
Canadian institutionsUniversity of British Columbia
Fundersnot available
KeywordsTrimerChemistryHydroxylationStereochemistryProtein quaternary structureMonooxygenaseFerredoxinSubstrate (aquarium)OxygenaseHemeDioxygenaseCrystallographyHelix (gastropod)Protein structureHistidineDimerProtein subunitBiochemistryCytochrome P450EnzymeBiology

Abstract

fetched live from OpenAlex

Abstract KshAB is a Rieske oxygenase (RO) in the aerobic steroid degradation pathways of bacteria. It is a monooxygenase responsible for the 9α‐hydroxylation of the nucleus of 3‐keto‐4‐ene steroids bearing short side chains at C17. It is composed of two domains arranged in a head‐to‐tail fashion to form the functional trimer. The N‐terminal Rieske domain harbors a Fe2S2cluster in which the two irons are coordinated by two cysteine and two histidine residues, respectively. The larger, C‐terminal catalytic domain contains a mononuclear nonheme iron coordinated by a His‐His‐Asp facial triad. Purified KshAB from Mycobacterium tuberculosis exhibits substrate specificities for 1,4‐androstadien‐3,17‐one and dioxygen 2‐3 orders of magnitude lower than those measured for other ROs and their best substrates. In agreement with the large fused‐ring substrate, the structure of KshA incorporates an active site channel and substrate binding pocket that are longer than those observed in other ROs, and positioned in a different relative orientation within the catalytic domain. KshA also possesses a C‐terminal helix which occupies a position not observed in other RO structures and which likely stabilizes trimeric quaternary structure. Finally, KshA exhibits a minimal core catalytic domain with respect to secondary structural elements that may prove archetypical for ROs.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Other · Consensus signal: none
Teacher disagreement score0.007
Threshold uncertainty score0.025

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0010.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0070.011

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.006
GPT teacher head0.216
Teacher spread0.210 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designNot applicable
Domainnot available
GenreOther

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2004
Admission routes1
Has abstractyes

Explore more

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