the conformational arrangement (α-helix, β-pleated sheet, etc.) of the backbone segments of a macromolecule such as a polypeptide chain of a protein without regard to the conformation of the side chains or the relationship to other segments, makromolekuli, nt valgu polüpeptiidahela ülesehitus (α-heeliks, β-kurrutatud leht jt), arvestamata külgahelate konformatsiooni või seost molekuli teiste segmentidega