Observing Changes in the Structure and Oligomerization State of a Helical Protein Dimer Using Solid-State Nanopores.
Protein analysis using solid-state nanopores is challenging due to limitations in bandwidth and signal-to-noise ratio. Recent improvements of those two aspects have made feasible the study of small peptides using solid-state nanopores, which have an advantage over biological counterparts in tunability of the pore diameter. Here, we report on the detection and characterization of peptides as small as 33 amino acids. Silicon nitride nanopores with thicknesses less than 10 nm are used to provide signal-to-noise (S/N) levels up to S/N ∼ 10 at 100 kHz. We demonstrate differentiation of monomer and dimer forms of the GCN4-p1 leucine zipper, a coiled-coil structure well studied in molecular biology, and compare with the unstructured 33-residue monomer. GCN4-p1 is sequence segment associated with homodimerization of the transcription factor General Control Nonderepressible 4 (GCN4), which is involved in the control of amino acid synthesis in yeast. The differentiation between two oligomeric forms demonstrates the capabilities of improved solid-state nanopore platforms to extract structural information involving short peptide structures.
Department of Physics and Astronomy, University of Pennsylvania , 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396, United States.
David J
DJ
Niedzwiecki
Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States.
Christopher J
CJ
Lanci
Department of Physics and Astronomy, University of Pennsylvania , 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396, United States.
Gabriel
G
Shemer
Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States.
Phillip S
PS
Cheng
Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States.
Jeffery G
JG
Saven
Department of Physics and Astronomy, University of Pennsylvania , 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396, United States.
Marija
M
Drndić
D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins / Q000737:chemistry; D019281:Dimerization; D058608:Nanopores / Q000648:ultrastructure*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000737:chemistry
D004268:DNA-Binding Proteins
GCN4; leucine zipper; nanopore; resistive-pulse; single-molecule