A 3-D View: IGF-1 with a Binding Protein

CPK Color Scheme

This page allows you to view the 3 dimensional structure of the Insulin-like growth factor 1 (IGF-1) protein bound by  the Insulin-like growth factor binding protein 5 (IGFBP5). Let's examine the structure and interactions of these two proteins in more detail below.

Reset and spin this complex.

Notice IGF-1 in yellow and the binding protein in green. This binding protein (the fifth identified for IGF-1) is thought to prohibit IGF-1 from interacting with the IGF-1 receptor, thus preventing the growth signal from being received (Zeslawski et al. 2001). Recent studies have suggested there may be more diverse effects than simply inhibitory, however (reviewed in Schneider et. al 2002).

Click here to view the disulfide bridges (in green) in this complex. There are three in IGF-1 and 2 in IGFBP5. Notice how the disulfide bridges appear to have a tremendous impact on the 3-dimensional structure of these two proteins.

Color the proteins by secondary structure characteristics. Alpha helices are pink, and beta sheets are yellow.

Click here to see which portion of IGF-1 is responsible for binding with various binding proteins. The amino acids 1-16 in IGF-1 have been shown to be important in binding protein interactions (Bayne et. al 1989); this button will make these residues yellow.

Click here to see how IGF-1 binds with its cellular receptor, IGF-1R. Amino acids 24 and 28-37 are recognized as crucial for binding (Bayne et. al 1989); these residues will become orange.

Click here to view the complex colored according to "anisotropic temperature." Essentially, parts of the protein that are more capable of movement are red, and more immobile portions of the protein are blue (Silva and Marcey 2007).


M. Bayne, Applebaum J., Underwood D., Chicci G., Green B., Hayes N., M. Cascieri. 1989. The C region of human insulin-like grwoth factor (IGF) I is required for high affinity binding to the type 1 IGF receptor. Journal of Biological Chemistry 264 (19): 11004-11008.

M. Schneider, Wolf E., Hoeflich A., H. Lahm. 2002. IGF-binding protein-5: a flexible player in the IGF system and effector on its own. Journal of Endocrinology 172(3): 423-440.

N. Silva and D. Marcey.  Intro to Jmol Scripting. The Online Macromolecular Museum Exhibits. <http://www.callutheran.edu/BioDev/omm/scripting/molmast.htm>. 7 April 2010.

 W. Zeslawski,  Beisel H.,  Kamionka M.,  Wenzel K.,  Engh R.,  Huber H.,  Lang K.,  T. Holak. 2001. The interaction of insulin-like growth factor 1 with the N-terminal domain of IGFBP5. The EMBO Journal 20(14): 3638-3644.

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