X-ray structure of a compound of cobalt with uridine 5'-monophosphate. Evidence for metal-phosphate bonding only.

An X-ray study of the crystal structure of a cobalt(II) complex with uridine 5'-monophosphate shows it to contain polymeric chains of composition [Co2(H2O)4 (5'-UMP)2]n. The cobalt atoms do not bind to the pyrimidine base moiety; instead each metal atom is octahedrally coordinated to four phosphate groups and two water molecules. Managanese(II) forms a similar compound.

X-ray structure of [Ru3 O2 (NH3)14]6+, cation of the cytological reagent Ruthenium Red.

The X-ray crystal structure of [Ru3 O2 (NH3)14] (S2 O3)3 . 4H2 O, the thiosulphate salt of Ruthenium Red, has been determined. The cation contains an essentially linear N-Ru-O-Ru-O-Ru-N backbone formed from three ruthenium coordination octahedra, giving an effectively cylindrical shape to the ion. Resonance Raman spectra are consistent with retention of this structure in solution.

The site of metal ion binding in a nickel derivative of adenosine 5'-monophosphate: an x-ray study.

Single-crystal X-ray methods have been used to characterize a nickel derivative of adenosine 5'-monophosphate, of stoicheiometry [Ni(5'-AMP)(H2O)5]-H2O. The metal atom binds to the N(7) position on the adenine base, with the five remaining octahedral coordination sites about nickel occupied by water molecules. The phosphate group is connected via intramolecular hydrogen bonds to coordinated water molecules.

Strong metal-oxygen interaction in uracils. X-ray crystal structure of bis-(1,3-dimethyluracil)dichlorocopper(II).

An X-ray structure determination showed that in the compound bis-(1,3-dimethyluracil)-dichlorocopper(II) the uracil moiety is strongly bonded to the metal via the O(4) atom. Changes in the i.r. spectra on metal binding are discussed. Details of the structural parameters have been deposited as Supplementary Publications SUP 50091 (3 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

X-ray evidence for metal-N-7 bonding in a hydrated manganese derivative of guanosine 5'-monophosphate.

Single-crystal X-ray studies of a manganese(II) derivative of guanosine 5'-monophosphate, [Mn(5'-GMP)(H(2)O)(5)],3H(2)O, have shown that it is isostructural with its nickel analogue. The manganese atom therefore is bonded to five water molecules with the remaining octahedral co-ordination site being occupied by N-7 of the nucleotide base. No direct metal-phosphate bonding is involved, but there are structure-stabilizing intramolecular hydrogen bonds between two phosphate oxygen atoms and co-ordinated water molecules.

Heavy metal-pyrimidine nucleotide interaction: x-ray structure of a cadmium derivative of cytidine 5'-monophosphate.

An X-ray crystal-structure determination has shown that the compound [Cd(5'-CMP)(H2O)],H2O has a polymeric structure in which each cadmium atom is bonded to five atoms: to the N(3) position on the base, to a phosphate oxygen from each of three other 5'-CMP groups and to a water molecule.

Multiplicity of cadmium binding sites in nucleotides: X-ray evidence for the involvement of O2' and O3' as well as phosphate and N7 in inosine 5'-monophosphate.

Single-crystal X-ray methods have been used to characterize a hydrated polymeric cadmium derivative of inosine 5'-monophosphate. In the structure there are two independent cadmium atoms, one of which binds to two ribose oxygen atoms, an N7 position on a base, and to three water molecules. The second metal atom binds to a phosphate oxygen, three water molecules, and to two N7 atoms, which are in cis-positions. For these last; the Cd-N bonds are appreciably out of the planes of the hypoxanthine bases so that the angle between these planes is only 31.4 degrees.

Differentiation-inducing factor from the slime mould Dictyostelium discoideum and its analogues. Synthesis, structure and biological activity.

Previous work has led to the identification of a novel class of effector molecules [DIFs (differentiation-inducing factors) 1-3] released from the slime mould Dictyostelium discoideum. These substances induce stalk-cell differentiation in Dictyostelium discoideum and are thought to act as morphogens in the generation of the prestalk/prespore pattern during development. The DIFs are phenylalkan-1-ones, with chloro, hydroxy and methoxy substitution on the benzene ring. DIFs 1-3 and a number of their analogues have been synthesized by using a simple two-step procedure, and each analogue has been characterized by m.s., u.v. and n.m.r. spectroscopy. The crystal structure of synthetic DIF-1 [1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl)hexan-1-one, was investigated. The specific biological activity of each analogue was determined in a bioassay, where isolated Dictyostelium amoebae are induced to differentiate into stalk cells. The major biologically active substance, DIF-1, caused 50% stalk-cell differentiation at 1.8 x 10(-10) M; the C4 alkyl homologue (DIF-2) and C6 homologue possessed 40 and 16% of the activity of DIF-1 respectively. Further increase or decrease in the alkyl chain length resulted in a marked decrease in specific activity. The pattern of substitution on the benzene ring is a major determinant of bioactivity, since the specific activities of the 2,4-dihydroxy-6-methoxy and trihydroxy analogues were less than 1% of that of DIF-1. Substitution of bromine in DIF-1 had little effect on bioactivity; in contrast the activity of monochloro-DIF-1 (DIF-3) was diminished. There was no evidence for antagonism or synergy between DIF-1 and any of its analogues. This series of analogues will facilitate further studies in the biological effects and mode of action of DIF-1.