Right-handed Z-DNA at ultrahigh resolution: a tale of two hands and the power of the crystallographic method.

The self-complementary L-d(CGCGCG) purine/pyrimidine hexanucleotide was crystallized in complex with the polyamine cadaverine and potassium cations. Since the oligonucleotide contained the enantiomeric 2'-deoxy-L-ribose, the Z-DNA duplex is right-handed, as confirmed by the ultrahigh-resolution crystal structure determined at 0.69 Å resolution.

-Adenosyl-L-Homocysteine Hydrolase Inhibition by a Synthetic Nicotinamide Cofactor Biomimetic.

-adenosyl-L-homocysteine (SAH) hydrolases (SAHases) are involved in the regulation of methylation reactions in many organisms and are thus crucial for numerous cellular functions. Consequently, their dysregulation is associated with severe health problems. The SAHase-catalyzed reaction is reversible and both directions depend on the redox activity of nicotinamide adenine dinucleotide (NAD) as a cofactor.

Crystallographic and SAXS studies of -adenosyl-l-homocysteine hydrolase from .

-Adenosyl-l-homocysteine hydrolase (SAHase) from the symbiotic bacterium (BeSAHase) was crystallized in four ligand complexes with (i) mixed adenosine (Ado) and cordycepin (Cord; 3'-deoxyadenosine), (ii) adenine (Ade), (iii) Ado and (iv) mixed 2'-deoxyadenosine (2'-dAdo) and Ade. The crystal structures were solved at resolutions of 1.84, 1.

An enzyme captured in two conformational states: crystal structure of S-adenosyl-L-homocysteine hydrolase from Bradyrhizobium elkanii.

S-Adenosyl-L-homocysteine hydrolase (SAHase) is involved in the enzymatic regulation of S-adenosyl-L-methionine (SAM)-dependent methylation reactions. After methyl-group transfer from SAM, S-adenosyl-L-homocysteine (SAH) is formed as a byproduct, which in turn is hydrolyzed to adenosine (Ado) and homocysteine (Hcy) by SAHase. The crystal structure of BeSAHase, an SAHase from Bradyrhizobium elkanii, which is a nitrogen-fixing bacterial symbiont of legume plants, was determined at 1.

Two isomorphous azastilbene derivatives: 1-(2-chlorobenzyl)-4-[(E)-2-(4-hydroxyphenyl)ethenyl]pyridinium chloride and 1-(2-bromobenzyl)-4-[(E)-2-(4-hydroxyphenyl)ethenyl]pyridinium bromide.

The crystal structures of the two title (E)-stilbazolium halogenates, C(20)H(17)ClNO(+)·Cl(-) and C(20)H(17)BrNO(+)·Br(-), are isomorphous, with an isostructurality index of 0.985. The azastyryl fragments are almost planar, with dihedral angles between the benzene and pyridine rings of ca 4.