Structural studies of a crystalline insulin analog complex with protamine by atomic force microscopy

Christopher M. Yip, Mark L. Brader, Bruce H. Frank, Michael R. DeFelippis, Michael Ward

Research output: Contribution to journalArticle

Abstract

Crystallographic studies of insulin-protamine complexes, such as neutral protamine Hagedorn (NPH) insulin, have been hampered by high crystal solvent content, small crystal dimensions, and extensive disorder in the protamine molecules. We report herein in situ tapping mode atomic force microscopy (TMAFM) studies of crystalline neutral protamine Lys(B28)Pro(B29) (NPL), a complex of Lys(B28)Pro(B29) insulin, in which the C-terminal prolyl and lysyl residues of human insulin are inverted, and protamine that is used as an intermediate time-action therapy for treating insulin-dependent diabetes. Tapping mode AFM performed at 6°C on bipyramidally tipped tetragonal rod- shaped NPL crystals revealed large micron-sized islands separated by 44-Å tall steps. Lattice images obtained by in situ TMAFM phase and height imaging on these islands were consistent with the arrangement of individual insulin- protamine complexes on the P41212 (110) crystal plane of NPH, based on a low-resolution x-ray diffraction structure of NPH, arguing that the NPH and NPL insulins are isostructural. Superposition of the height and phase images indicated that tip-sample adhesion was larger in the interstices between NPL complexes in the (110) crystal plane than over the individual complexes. These results demonstrate the utility of low-temperature TMAFM height and phase imaging for the structural characterization of biomolecular complexes.

Original languageEnglish (US)
Pages (from-to)466-473
Number of pages8
JournalBiophysical Journal
Volume78
Issue number1
StatePublished - 2000

Fingerprint

Protamines
Atomic Force Microscopy
Insulin
Isophane Insulin
Islands
X-Rays
Temperature

ASJC Scopus subject areas

  • Biophysics

Cite this

Structural studies of a crystalline insulin analog complex with protamine by atomic force microscopy. / Yip, Christopher M.; Brader, Mark L.; Frank, Bruce H.; DeFelippis, Michael R.; Ward, Michael.

In: Biophysical Journal, Vol. 78, No. 1, 2000, p. 466-473.

Research output: Contribution to journalArticle

Yip, CM, Brader, ML, Frank, BH, DeFelippis, MR & Ward, M 2000, 'Structural studies of a crystalline insulin analog complex with protamine by atomic force microscopy', Biophysical Journal, vol. 78, no. 1, pp. 466-473.
Yip, Christopher M. ; Brader, Mark L. ; Frank, Bruce H. ; DeFelippis, Michael R. ; Ward, Michael. / Structural studies of a crystalline insulin analog complex with protamine by atomic force microscopy. In: Biophysical Journal. 2000 ; Vol. 78, No. 1. pp. 466-473.
@article{f8af54cc2812441b87653076fb79ba86,
title = "Structural studies of a crystalline insulin analog complex with protamine by atomic force microscopy",
abstract = "Crystallographic studies of insulin-protamine complexes, such as neutral protamine Hagedorn (NPH) insulin, have been hampered by high crystal solvent content, small crystal dimensions, and extensive disorder in the protamine molecules. We report herein in situ tapping mode atomic force microscopy (TMAFM) studies of crystalline neutral protamine Lys(B28)Pro(B29) (NPL), a complex of Lys(B28)Pro(B29) insulin, in which the C-terminal prolyl and lysyl residues of human insulin are inverted, and protamine that is used as an intermediate time-action therapy for treating insulin-dependent diabetes. Tapping mode AFM performed at 6°C on bipyramidally tipped tetragonal rod- shaped NPL crystals revealed large micron-sized islands separated by 44-{\AA} tall steps. Lattice images obtained by in situ TMAFM phase and height imaging on these islands were consistent with the arrangement of individual insulin- protamine complexes on the P41212 (110) crystal plane of NPH, based on a low-resolution x-ray diffraction structure of NPH, arguing that the NPH and NPL insulins are isostructural. Superposition of the height and phase images indicated that tip-sample adhesion was larger in the interstices between NPL complexes in the (110) crystal plane than over the individual complexes. These results demonstrate the utility of low-temperature TMAFM height and phase imaging for the structural characterization of biomolecular complexes.",
author = "Yip, {Christopher M.} and Brader, {Mark L.} and Frank, {Bruce H.} and DeFelippis, {Michael R.} and Michael Ward",
year = "2000",
language = "English (US)",
volume = "78",
pages = "466--473",
journal = "Biophysical Journal",
issn = "0006-3495",
publisher = "Biophysical Society",
number = "1",

}

TY - JOUR

T1 - Structural studies of a crystalline insulin analog complex with protamine by atomic force microscopy

AU - Yip, Christopher M.

AU - Brader, Mark L.

AU - Frank, Bruce H.

AU - DeFelippis, Michael R.

AU - Ward, Michael

PY - 2000

Y1 - 2000

N2 - Crystallographic studies of insulin-protamine complexes, such as neutral protamine Hagedorn (NPH) insulin, have been hampered by high crystal solvent content, small crystal dimensions, and extensive disorder in the protamine molecules. We report herein in situ tapping mode atomic force microscopy (TMAFM) studies of crystalline neutral protamine Lys(B28)Pro(B29) (NPL), a complex of Lys(B28)Pro(B29) insulin, in which the C-terminal prolyl and lysyl residues of human insulin are inverted, and protamine that is used as an intermediate time-action therapy for treating insulin-dependent diabetes. Tapping mode AFM performed at 6°C on bipyramidally tipped tetragonal rod- shaped NPL crystals revealed large micron-sized islands separated by 44-Å tall steps. Lattice images obtained by in situ TMAFM phase and height imaging on these islands were consistent with the arrangement of individual insulin- protamine complexes on the P41212 (110) crystal plane of NPH, based on a low-resolution x-ray diffraction structure of NPH, arguing that the NPH and NPL insulins are isostructural. Superposition of the height and phase images indicated that tip-sample adhesion was larger in the interstices between NPL complexes in the (110) crystal plane than over the individual complexes. These results demonstrate the utility of low-temperature TMAFM height and phase imaging for the structural characterization of biomolecular complexes.

AB - Crystallographic studies of insulin-protamine complexes, such as neutral protamine Hagedorn (NPH) insulin, have been hampered by high crystal solvent content, small crystal dimensions, and extensive disorder in the protamine molecules. We report herein in situ tapping mode atomic force microscopy (TMAFM) studies of crystalline neutral protamine Lys(B28)Pro(B29) (NPL), a complex of Lys(B28)Pro(B29) insulin, in which the C-terminal prolyl and lysyl residues of human insulin are inverted, and protamine that is used as an intermediate time-action therapy for treating insulin-dependent diabetes. Tapping mode AFM performed at 6°C on bipyramidally tipped tetragonal rod- shaped NPL crystals revealed large micron-sized islands separated by 44-Å tall steps. Lattice images obtained by in situ TMAFM phase and height imaging on these islands were consistent with the arrangement of individual insulin- protamine complexes on the P41212 (110) crystal plane of NPH, based on a low-resolution x-ray diffraction structure of NPH, arguing that the NPH and NPL insulins are isostructural. Superposition of the height and phase images indicated that tip-sample adhesion was larger in the interstices between NPL complexes in the (110) crystal plane than over the individual complexes. These results demonstrate the utility of low-temperature TMAFM height and phase imaging for the structural characterization of biomolecular complexes.

UR - http://www.scopus.com/inward/record.url?scp=0034030934&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034030934&partnerID=8YFLogxK

M3 - Article

C2 - 10620310

AN - SCOPUS:0034030934

VL - 78

SP - 466

EP - 473

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 1

ER -