Chapter 3 Alpha-domain structures

Coiled-coil Helical bundle

Globin fold

COILED-COIL STRUCTURES

Examples: mammals' hair (including wool), hooves, nails, rhinoceros horns, much of the outer layer of skin

α-Keratin: a Coiled Coil

Coiled-coil α helices contain a repetitive heptad amino acid sequence pattern

Salt bridges can stabilize coiled-coil structure

Packing side chains in the hydrophobic core of coiled-coil structure: “knobs in

holes” model

Coiled Coils in The Nature: Protein Binding

[Marsden and Kros (2010) Angew. Chem. Int. Ed.]

Coiled Coils in The Nature: Structural Functions

[Marsden and Kros (2010) Angew. Chem. Int. Ed.]

NuMa (Nuclear Mitotic Apparatus): a fibrous nucleoskeletal protein

Coiled Coils in The Nature: Dynamic Functions

[Marsden and Kros (2010) Angew. Chem. Int. Ed.]

HELIX BUNDLE STRUCTURES

The four-helix bundle is a common domain structure in α proteins

http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query_old?uid=10543964&form=6&db=m&Dopt=b

Alpha-helical domains are sometimes large and complex

Bulgecin, a glycopeptide inhibitor

70-kDa soluble lytic transglycosylase (SLT70), a target for bulgecin

GLOBIN FOLD

The globin fold is present in myoglobin and hemoglobin

The globin fold has been preserved during evolution

Ridges of one α helix fit into grooves of an adjacent helix

ridge

groove

The “ridges in grooves” model

Globin fold

Four-helix bundle

Sickle-cell hemoglobin confers resistance to malaria: E6V mutation