Acta Crystallographica Section B

Structural Science

Volume 60, Part 5 (October 2004)

research papers

Acta Cryst. (2004). B60, 569-577 [ doi:10.1107/S0108768104014569 ]

A crystallographic titration of the dipeptide L-isoleucyl-L-isoleucine

C. H. Görbitz

Abstract: The dipeptide L-Ile-L-Ile has been crystallized in four different protonation states, including as a cation, a zwitterion and an anion, as well as a dimeric cation in which two peptide molecules, linked by a strong -COOHOOC- hydrogen bond, share an overall positive charge of +1. This unprecedented series of crystal structures exhibits differences in hydrogen-bonding capabilities, conformational properties and molecular packing arrangements. The crystallization of L-Ile-L-Ile as an anion was achieved by slow evaporation from an NH₃(l) solution to give the first ever ammonium salt of a peptide (or amino acid).

Keywords: crystallographic titration; L-isoleucyl-L-isoleucine; protonation states; peptides; hydrogen bonding; conformational properties; molecular packing.


	Structure factor file (CIF format) (97.5 kbytes) Contains datablock ii3121

	Structure factor file (CIF format) (182.9 kbytes) Contains datablock iic21212

	Structure factor file (CIF format) (342.5 kbytes) Contains datablock ii

	Structure factor file (CIF format) (153.3 kbytes) Contains datablock ii2

Notes:

To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.

The download button will force most browsers to prompt for a file name to store the data on your hard disk.

Where possible, images are represented by thumbnails.

Search: From to Advanced search