Impact of natural variation in bacterial F17G adhesins on crystallization behaviour.

• Since the introduction of structural genomics, the protein has been recognized as the most important variable in crystallization. Recent strategies to modify a protein to improve crystal quality have included rationally engineered point mutations, truncations, deletions and fusions. Five naturally occurring variants, differing in 1-18 amino acids, of the 177-residue lectin domain of the F17G fimbrial adhesin were expressed and purified in identical ways. For four out of the five variants crystals were obtained, mostly in non-isomorphous space groups, with diffraction limits ranging between 2.4 and 1.1 A resolution. A comparative analysis of the crystal-packing contacts revealed that the variable amino acids are often involved in lattice contacts and a single amino-acid substitution can suffice to radically change crystal packing. A statistical approach proved reliable to estimate the compatibilities of the variant sequences with the observed crystal forms. In conclusion, natural variation, universally present within prokaryotic species, is a valuable genetic resource that can be favourably employed to enhance the crystallization success rate with considerably less effort than other strategies.

Subject headings

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

Adhesins

Bacterial

chemistry

genetics

Amino Acid Sequence

Crystallization

methods

Crystallography

X-Ray

Disaccharides

chemistry

Escherichia coli Proteins

chemistry

genetics

Models

Molecular

Molecular Sequence Data

Protein Structure

Tertiary

Sequence Alignment

Variation (Genetics)

Publication and Content Type

ref (subject category)

art (subject category)