Collagen forms a triple helix structure which consists of three tightly coiled polyproline II-type (PPII) strands with the repeating amino acid motif Xaa-Yaa-Gly, where Xaa and Yaa are often proline (Pro) and hydroxproline (Hyp), respectively. The thermal and mechanical stability of the collagen triple-helix is a complex balance between several factors, e.g. sterical influences of substituents, stereoelectronic effects, or interstrand interactions. On the basis of computational studies, we have analyzed the influence of these effects and demonstrate that even comparatively small effects, like the stereoelectronic gauche-effect, and intramolecular hydrogen-bonding can have an impact on the triple-helix stability. In addition, our results suggest that hydrogen bond-like interactions perpendicular to the helix axis increase the stiffness of collagen. Our studies provide a deeper insight into the structure-directing factors in collagenous materials and will help to improve the synthesis of collagen-like biomaterials. (C) 2013 Elsevier B.V. All rights reserved.