Protein fold class

α+β proteins

α+β proteins are a class of structural domains in which the secondary structure is composed of α-helices and β-strands that occur separately along the backbone. The β-strands are therefore mostly antiparallel.^[1]

Common examples include the ferredoxin fold, ribonuclease A, and the SH2 domain.

α/β proteins

α/β proteins is a class of structural domains in which the secondary structure is composed of alternating α-helices and β-strands along the backbone. The β-strands are therefore mostly parallel.^[2]

Common examples include the flavodoxin fold, the TIM barrel and leucine-rich-repeat (LRR) proteins such as ribonuclease inhibitor.

all-α proteins

An all-α proteins is a class of structural domains in which the secondary structure is composed entirely of α-helices, with the possible exception of a few isolated β-sheets on the periphery.

Common examples include the bromodomain, the globin fold and the homeodomain fold.

all-β proteins

An all-β proteins is a class of structural domains in which the secondary structure is composed entirely of β-sheets, with the possible exception of a few isolated α-helices on the periphery.

Common examples include the SH3 domain, the beta-propeller domain, the immunoglobulin fold and B3 DNA binding domain.

See also

• SCOP database
• CATH database
• FSSP database

References