Great Rings

Brooks achieves a representation of classes of objects by an unusual data structure we will call this a "Brooks Data Structure" — BDS. We can adapt the BDS to a LISP-coded specification of a macromolecule as follows the macromolecule is to be described by a TREE, the ROOT of which is the coarsest characterization of the molecule. For a macrocycle, the ROOT would be the great ring for a branched chain it would be the longest backbone. This ROOT would be a list, the basic data structure of LISP, with each element in the list a data set defining a generalized cylinder. 

Like a great ring of pure and endless light... 

Figure 7. Inner great rings of natural macrocyclic ligand systems...

As an additional example of the SEC-MALDI method, Casazza et al. [71] obtained Nylon6 by suspension polymerization. Methanol was used to eliminate small cycles (mostly monomer, dimer, and trimer) and injected the sample in an SEC apparatus. Figure 45.15 contains the SEC trace. The SEC trace is bimodal, with two bands at 12 and 15 min, respectively. The second band is labeled GR, a shorthand notation for Great Rings. The MALDI spectrum of the band at 12 min displayed a series of peaks which form an envelope... 

FIGURE 45.15 SEC trace of a Nylon6 sample obtained by suspension polymerization and washed with methanol to eliminate the cyclic monomer, the cyclic dimer, and so on. The GR peak is due to Great Rings. Reproduced from Casazza et al. [71], copyright 2007 with permission, a.i., arbitrary intensity units. 

It is now established that the heme, at least in vertebrate catalase, is protoheme (186, 243). Apparently however, the four iron atoms of most catalase preparations do not all belong to heme. In fact a blue iron-containing pigment is nearly always obtainable from catalase preparations in addition to protoheme (5, 185, 187). This is now known to be related to biliverdin (116). It is thought to arise as an oxidation product of protoheme in which one of the methin bridges of the great ring is broken as shown in the formula (112) ... 

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