conformation

Conformation is the three-dimensional arrangement of atoms in a molecule or macromolecule, especially as determined by rotation about single bonds. It refers to the spatial orientation that a molecule can assume without breaking chemical bonds; different arrangements of the same molecule are called conformers or conformational isomers. The term contrasts with constitution (connectivity) and configuration (relative order of atoms that cannot be changed without breaking bonds).

In chemistry, conformational isomerism arises from rotation about single bonds. Classic examples include the staggered and eclipsed forms of ethane and the chair and boat forms of cyclohexane. The relative stability of conformers depends on steric interactions, torsional strain, and electronic effects; at a given temperature, populations follow the energy landscape and interconvert over time.

In biochemistry, many biological macromolecules adopt specific conformations that determine function. Proteins fold into three-dimensional structures, and their conformations can change during activity, regulation, or interactions with ligands. Nucleic acids and complex carbohydrates also exhibit conformational flexibility. Abnormal conformations or misfolding can lead to aggregates and disease states.

In animal breeding and veterinary contexts, conformation describes the external structure and appearance of an animal, including proportions, alignment, and movement. Breed standards specify desired conformational traits, and selection based on these traits aims to optimize performance or elegance. Overemphasis on conformation can also impact health and welfare if it neglects functional or structural integrity.

Conformation is also used in materials science and structural biology to describe the shape and arrangement of molecules within solids and assemblies, where conformational changes can influence properties such as elasticity, binding, and reactivity.