Abstract: In some embodiments, the present invention provides a protein comprising amino acids in the following sequence L(X)n=14X3(X)n=1X1(X)n=1E(X)n=4P(X)n=1NR(X)n=3S(X)n=4D(X)n=2G(X)n=7Y(X)n=4Y (X)n=32-34X2 (SEQ ID NO: 128), wherein each X independently represents any naturally occurring amino acid residue and n indicates the number of amino acid residues represented by the respective paranthetical at that position, wherein: a) X1 is selected from the group consisting of S, C, T, M, V, Y, N, P, L, G, Q, A, I, D, W, H, or E, wherein if X1 is L, H or V, then X3 is D; and/or b) X2 is selected from the group consisting of H, L, S or V. In some embodiments, the present invention also provides a protein comprising amino acids in the sequence set forth by SEQ ID NO: 38 or SEQ ID NO: 39, except that: the amino acid at position 406 is an amino acid other than F; and/or the amino acid at position 474 is an amino acid other than N.