Structure-Based Engineering of Internal Cavities in Coiled-Coil Peptides

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• 作者：Maneesh K. Yadav ; James E. Redman ; Luke J. Leman ; Julietta M. Alvarez-Gutié ; rrez ; Yanming Zhang ; C. David Stout ; and M. Reza Ghadiri
• 刊名：Biochemistry
• 出版年：2005
• 出版时间：July 19, 2005
• 年：2005
• 卷：44
• 期：28
• 页码：9723 - 9732
• 全文大小：1049K
• 年卷期：v.44,no.28(July 19, 2005)
• ISSN：1520-4995

文摘

Cavities and clefts are frequently important sites of interaction between natural enzymes orreceptors and their corresponding substrate or ligand molecules and exemplify the types of molecularsurfaces that would facilitate engineering of artificial catalysts and receptors. Even so, structuralcharacterizations of designed cavities are rare. To address this issue, we performed a systematic study ofthe structural effects of single-amino acid substitutions within the hydrophobic cores of tetrameric coiled-coil peptides. Peptides containing single glycine, serine, alanine, or threonine amino acid substitutions atthe buried L9, L16, L23, and I26 hydrophobic core positions of a GCN4-based sequence were synthesizedand studied by solution-phase and crystallographic techniques. All peptides adopt the expected tetramericstate and contain tunnels or internal cavities ranging in size from 80 to 370 ų. Two closely relatedsequences containing an L16G substitution, one of which adopts an antiparallel configuration and one ofwhich adopts a parallel configuration, illustrate that cavities of different volumes and shapes can beengineered from identical core substitutions. Finally, we demonstrate that two of the peptides (L9G andL9A) bind the small molecule iodobenzene when present during crystallization, leaving the general peptidequaternary structure intact but altering the local peptide conformation and certain superhelical parameters.These high-resolution descriptions of varied molecular surfaces within solvent-occluded internal cavitiesillustrate the breadth of design space available in even closely related peptides and offer valuable modelsfor the engineering of de novo helical proteins.