Structure cristalline et moléculaire de la nor-19 testosterone

Précigoux, G.; Busetta, B.; Courseille, C.

doi:10.1107/s0567740875005638

Cited by 36 publications

(14 citation statements)

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“…Colourless needles crystallized from saturated solution in ethanol kept at 273 K in the refrigerator. Unit-cell parameters in this paper differ from those reported by Precigoux et aL (1975). Cell parameters Uetermined accurately on Nonius CAD-4 diffractometer by least-squares analysis of 25 reflections with 20 _> 30 °.…”

contrasting

confidence: 47%

“…It is of interest to determine the conformational features of 19-nortestosterone accurately and compare them with those of testosterone. Several crystallographic investigations of testosterone are known (Duax & Norton, 1975) but so far only one crystal structure of 19-nortestosterone has been studied (Precigoux et al, 1975), where atoms of ring A are disordered. Since it is known from the literature that steroids often exhibit polymorphism depending on the solvent of crystallization (Busetta, Courseille, Leroy & Hospital, 1972;Roberts, Petterson, Sheldrick, Isaacs & Kennard, 1973;Busetta, Courseille, Fornies-Marquina & Hospital, 1972;Courseille, Precigoux, Leroy & Busetta, 1973), it was considered worthwhile to attempt crystallization of the title compound in different solvents, hopefully to obtain a new crystal form.…”

mentioning

confidence: 99%

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Conformational flexibility in androgenic steroids: the structure of a new form of (+)-17β-hydroxy-19-nor-4-androsten-3-one (19-nortestosterone), C18H26O2

Bhadbhade¹,

Venkatesan²

1984

Acta Crystallogr C

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contrasting

confidence: 47%

mentioning

confidence: 99%

Conformational flexibility in androgenic steroids: the structure of a new form of (+)-17β-hydroxy-19-nor-4-androsten-3-one (19-nortestosterone), C18H26O2

Bhadbhade¹,

Venkatesan²

1984

Acta Crystallogr C

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“…Two types of conformational change have been shown to affect the absorption and IR spectra of enones, namely (1) variation of the torsional angle w , 03-C3-C4-C5, and (2) twisting and pyramidilization of the vinyl group. The angle, w , has been observed to be close to 180" in two crystal forms of 19-nortestosterone (Precigoux et al, 1975;Bhadbade & Venkatesan, 1984). Variation of w from 180" is expected to produce blueshifted absorption maxima and raised vibrational frequencies (House, 1983;Gawronski, 1989).…”

Section: A Con Formational Change In 19-nortestosterone Is Unlikelymentioning

confidence: 93%

Substrate polarization by residues in Δ⁵‐3‐ketosteroid isomerase probed by site‐directed mutagenesis and UV resonance Raman spectroscopy

Austin

Kuliopulos

et al. 1992

Protein Science

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A5-3-Ketosteroid isomerase (KSI: EC 5.3.3.1) of Pseudomonas testosteroni catalyzes the isomerization of A5-3-ketosteroids to A4-3-ketosteroids by the stereospecific transfer of the steroid 40-proton to the 60-position, using Tyr-14 as a general acid and Asp-38 as a base. Ultraviolet resonance Raman (UVRR) spectra have been obtained for the catalytically active double mutant Y55F + Y88F, which retains Tyr-14 as the only tyrosine residue (referred to as the Y140 mutant), and the Y14F mutant, which has 50,000-fold lower activity. The UVRR results establish that binding of the product analog and competitive inhibitors 19-nortestosterone or 4-fluoro-19-nortestosterone to the Y140 mutant does not result in the formation of deprotonated Tyr-14. The UVRR spectra of the steroid inhibitors show large decreases in the vinyl and carbonyl stretching frequencies on binding to the Y140 enzyme but not on binding to the Y14F enzyme. These changes cannot be mimicked by protonation of the steroids. For 19-nortestosterone, the vinyl and carbonyl stretching frequencies shift down (with respect to the values in aqueous solution) by 18 and 27 cm", respectively, on binding to Y140 KSI. It is proposed that the changes in the steroid resonance Raman spectrum arise from polarization of the enone moiety via the close proximity of the charged Asp-38 side chain to the vinyl group and the directional hydrogen bond between Tyr-14 and the 3-carbonyl oxygen of the steroid enone. The 230-nm-excited UVRR spectra do not, however, show changes that are characteristic of strong hydrogen bonding from the tyrosine hydrogen. It is proposed that this hydrogen bonding is compensated by a second hydrogen bond to the Tyr-14 oxygen from another protein residue.UVRR spectra of the Y14, enzyme obtained using 200 nm excitation show enhancement of the amide I1 and S Raman bands. The secondary structure of KSI was estimated from the amide I1 and S intensities and was found to be low in a-helical structure. The a-helix content was estimated to be in the range of 0-25% (i.e., 10 15%).

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“…The A 4 A ring has an inverted lfl,2a- An identical disorder of ring A was observed for one of the two independent molecules in the crystal structure of nortestosterone (Precigoux, Busetta, Courseille & Hospital, 1975). Ring A was found to have a normal half-chair conformation as well as an inverted half-chair conformation in a 2:1 ratio, whereas in the ordered molecule the A ring has an intermediate 1 a,2fl-half-chair/2a-sofa conformation.…”

mentioning

confidence: 85%

Structure of 13-ethyl-17β-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one (3-ketodesogestrel)

Geerestein¹,

Kanters²,

Kroon³

1987

Acta Crystallogr C

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Abstract. C22H2gO2, Mr= 324.46, monoclinic, P2 l, a=6.653(1), b= 18.413(1), c=7.9653(8)A, fl= 107-49 (1) °, V= 930.6 (2) A 3, Z = 2, Dx= 1.158gcm -3, 2(MoKa) =0.71073/~, /z (MoKa) = 0.7 cm -l, F(000) = 352, room temperature, R = 0.053 for 1910 unique reflections with I > 2.50(/). The ethyl group is in the usual trans conformation relative to the C/D ring junction. The A ring is statistically disordered (1:1) and shows a normal la,2fl-half-chair as well as an inverted lfl,2a-half-chair conformation. Molecular mechanics gives a steric energy difference of 4 kJ mo1-1 between the minimized normal and inverted half-chair structures in favour of the normal l a,2fl-half-chair conformation. The steroid molecules are hydrogenbonded head to tail.

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Structure cristalline et moléculaire de la nor-19 testosterone

Cited by 36 publications

References 3 publications

Conformational flexibility in androgenic steroids: the structure of a new form of (+)-17β-hydroxy-19-nor-4-androsten-3-one (19-nortestosterone), C18H26O2

Conformational flexibility in androgenic steroids: the structure of a new form of (+)-17β-hydroxy-19-nor-4-androsten-3-one (19-nortestosterone), C18H26O2

Substrate polarization by residues in Δ⁵‐3‐ketosteroid isomerase probed by site‐directed mutagenesis and UV resonance Raman spectroscopy

Structure of 13-ethyl-17β-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one (3-ketodesogestrel)

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Structure cristalline et moléculaire de la nor-19 testosterone

Cited by 36 publications

References 3 publications

Conformational flexibility in androgenic steroids: the structure of a new form of (+)-17β-hydroxy-19-nor-4-androsten-3-one (19-nortestosterone), C18H26O2

Conformational flexibility in androgenic steroids: the structure of a new form of (+)-17β-hydroxy-19-nor-4-androsten-3-one (19-nortestosterone), C18H26O2

Substrate polarization by residues in Δ5‐3‐ketosteroid isomerase probed by site‐directed mutagenesis and UV resonance Raman spectroscopy

Structure of 13-ethyl-17β-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one (3-ketodesogestrel)

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Substrate polarization by residues in Δ⁵‐3‐ketosteroid isomerase probed by site‐directed mutagenesis and UV resonance Raman spectroscopy