X-ray crystallography is the current gold standard of structural biology, but many proteins remain recalcitrant to crystallization. An emerging technique is the use of crystallization chaperones, which form a complex with a client protein, increasing solubility and providing additional hydrophilic residues to form crystal contacts and drive crystal formation.  We aim to create general crystallization chaperones by engineering antibody fragments to bind specific peptides. These chaperones span a range of biophysical characteristics and sizes - including nanobody, scFv and Fab - and can be readily used in the crystallization of various soluble and membrane proteins containing the target peptide, including GPCRs. We further aim to analyze the energetics of crystal contact formation with the goal of engineering proteins for improved crystallization.