Structure of DL-selenomethionine, C5H11NO2Se

Abstract

A view of the structure along a is given in Fig. 2. The structure is characterized by a strong hydrogen-bonded network, details of which are given in (2), c= 17.082 (4)A, fl= 101.63 (1) °, V= 780.0 (7) A 3, Z= 4, O m = 1.67, D x = 1.76 g cm -3, 2(CuKct) = 1.5418/k, g= 61.8 cm -1, F(000) = 392, T= 294 K. Final R = 0.079 for 1391 observed reflections. The crystal structure is found to be isomorphous to that of the a-form of DL-methionine. The two Se-C bond lengths are 1.938(4) and 1.907(8)A, and the C-Se-C angle is 98.9 (3) °, slightly smaller than the C-S-C angle.

Structural Modeling of Djenkolic Acid with Sulfur Replaced by Selenium and Tellurium

“…They are also in accordance with later published sources [8,10,11]. As for the same distances in DjSe, they are identical with those reported on the basis of X-ray studies (1.899–1.97 Å) [9,13]. The X-ray data for DjTe are missing in literature, so we compared our value with data for the C-Te distance characteristic of tellurium-containing organic compounds, which is 2.158 Å [15] exactly the same as found in our present research, and as estimated for telluromethionine earlier [8].…”

“…As follows from Table 1, Table 2 and Table 3, the bond lengths C(1)-C(2), C(2)-C(3), C(5)-C(6), C(6)-C(7), are the same in the three groups of conformers presented. The typical C-C bond lengths (1.50–1.53 Å) in isolated molecules neither increase along the chain from C(1) to C(7) nor depart in a significant manner from the normal single-bond value of 1.542 Å as it occurs in the solid dl -selenomethionine [9]. All distances C-N are exactly the same (1.46 Å).…”

“…The main crystallographic data obtained for methionine and selenomethionine so far comprise the crystal structure of d,l -alanylmethionine [10], the crystal structure of the α and β forms of d,l -methionine [11] and the crystal structure of d,l -selenomethionine [9], as well as the crystal and molecular structure of d,l -methionine nitrate [12]. The latest contribution to this topic is a report on the structure and dynamics of l -selenomethionine in the solid state [13] which successfully combines X-ray studies and solid state NMR spectroscopy.…”

A Combined Experimental and Quantum Chemistry Study of Selenium Chemical Shift Tensors

“…The crystal structures for compounds 1 − 16 have previously been determined by X-ray diffraction (XRD). − The atomic coordinates for compound 12 could not be generated from the report in the literature 100 and were determined from a nonrelativistic geometry optimization using ADF basis sets of similar quality to those used in the magnetic shielding tensor calculations. All DFT calculations were carried out on isolated molecules using the non-hydrogen atomic coordinates, determined from the crystal structures where possible.…”

Selenomethionyl proteins produced for analysis by multiwavelength anomalous diffraction (MAD): a vehicle for direct determination of three-dimensional structure.

“…Equally important, the resulting selenomethionyl proteins appear to be essentially isostructural with their natural methionyl counterparts. That this is so could be anticipated from the isomorphism between crystal structures of D,L methionine and D,L selenomethionine (Rajeswaran and Parthasarathy, 1984) and the remarkable tolerance of protein structure to site-directed point mutation. The isomorphism between natural and selenomethionyl crystal structures that is demonstrated here for T4 and E. coli thioredoxins has now been extended to interleukin ICa (IL-la) Hendrickson and Teeter (1981) The Bijvoet diffraction ratio is computed from < IAFAh > =q-2f" and the dispersive diffraction ratio is < AF± > =q-If' (xi)-f'(Xj)I where q = vI/NA/2Np/Zeff .…”