Strands a, h, c, and f make up the flat, inner sheet of the jelly roll and are involved in trimer contacts. Notice that the amino and carboxy strands are packed together in the inner sheet. The higly curved, outer sheet is made up of strands b, g, d, and e which form the outer surface of the trimer. Strand b in this outer sheet is interrupted, which is unusual in a beta-sandwich, at its amino terminus (residue 26) with a 20 amino acid chain that forms strands a1 and b1. These two strands surround the two sheets at the amino terminal edge and provide stability to this structure (Eck, 1989). There are three helical segments in the TNF-alpha monomer, only one can be seen to the right in magenta. None of the helices extend more than one full term. Residues making up these helices are 106-110, 138-142, and 145-150 (Eck, 1989). The TNF-alpha monomer also contains a disulfide bridge that serves as a connection between the loop connecting strands c and d with the loop conecting strands e and f. Residues 69 and 107 form this disulfide bond (Eck, 1989). Click here to see! For more information about TNF click here! To return to the title page, click here!
sarauehl@uwec.edu
