Details

Autor(en) / Beteiligte

• Huh, C G
• Aldrich, J
• Mottahedeh, J
• Kwon, H
• Johnson, C
• Marsh, R

Titel

Cloning and characterization of Physarum polycephalum tectonins. Homologues of Limulus lectin L-6

Ist Teil von

• The Journal of biological chemistry, 1998-03, Vol.273 (11), p.6565-6574

Ort / Verlag

United States

Erscheinungsjahr

1998

Quelle

MEDLINE

Beschreibungen/Notizen

• Previous investigators have reported the presence of two dominant proteins, tectonin I (25 kDa) and tectonin II (39 kDa), in nuclei and nuclear matrix from plasmodia of Physarum polycephalum. We demonstrate, by a modification of the nuclear isolation protocol and by protease sensitivity, that the tectonins are not nuclear proteins but rather are located on the exterior surface of the plasma membrane. We report the sequences of cDNAs of tectonins I and II, which encode 217 and 353 amino acids, respectively. Tectonin I is homologous to the C-terminal two-thirds of tectonin II. Both proteins contain six tandem repeats that are each 33-37 amino acids in length and define a new consensus sequence. Homologous repeats are found in L-6, a bacterial lipopolysaccharide-binding lectin from horseshoe crab hemocytes. The repetitive sequences of the tectonins and L-6 are reminiscent of the WD repeats of the beta-subunit of G proteins, suggesting that they form beta-propeller domains. Tectonin II has an additional N-terminal domain that includes a 47-residue sequence highly similar to the galactoside-binding sequence of the B-chain of ricin. The tectonins may be lectins that function as part of a transmembrane signaling complex during phagocytosis.