Why Sulfur and Why Methionine Starts: The Chrysene Junction, the Central Pair of an Even Cluster, and a Disulfide Across the Gap

Abstract

The corpus establishes that exactly two of the twenty structures require an element the carrier cannot supply, and places them under a hypothesis about the medium which it states and declines to establish. Two questions survive: why the same element should be required twice, and why a reading should have a beginning. This paper answers both at one object.

Where two poly-A-chrysene complexes meet chrysene to chrysene, with no intervening nucleobase, the regularity of the strand fails. The cell spanning the meeting has six vessels; six is even; and a cell of even count has no central vessel but a central pair — the two facing units. The corpus's localisation rule requires an odd count, so such a cell falls outside it rather than excepting it, and it yields two residues instead of one. Both are the corpus's published rows, used unamended, one on each facing unit.

The two residues share no atom and no bond: nothing connects them through the carrier, and the disulfide that joins them is what makes the cell one reaction rather than two. It closes across the π-stacking gap without distortion, the lateral register of a stacked pair being free where the exocyclic directions of a single plane are not, and the sense of the internal sulfur is forced. The cell is asymmetric before anything happens — in fragmentation, in sulfur site, and in reading direction — and all three distinguish the same unit; the electron balance, derived atom by atom, adds no fourth asymmetry and closes at one remnant level only, leaving both termini at the aldehyde level.

The reading is then taken off the reaction and not assumed. An alternating hexamer determines its reading only up to one position, changing the frame and changing the phase being indistinguishable there; the junction supplies exactly that one datum, which is what setting a frame means. Of the frame group only face inversion relates the two codons of a junction, and the case that proves it is the start codon itself, every window of an alternating hexamer being a palindrome. One position then decides start and stop together: a purine there terminates the incoming reading and withholds the outgoing start in a single event, so termination is the failure of a reaction to complete — a structure forms and is not released — rather than a residue assigned to a codon.

One consequence reaches back. Because face inversion is position-wise complementation, the two codons of a junction are complementary of necessity, and they are the corpus's unique complementary pair of seeded slots with both slots of size two. The corpus places these same two structures at complementary slots under a hypothesis it states and declines to establish; at a junction that hypothesis is a consequence.

The account rests on five premises of its own — that a junction forms, that a structure is released only at a narrow outer register, that the sulfur arrives bonded, that neither sulfur afterwards migrates, and that the two outer bases are complementary — and on one import. No energy is computed and no barrier estimated. The two residues are frame-related in the assignment structural consistency selects and not in the observed mapping, so the corpus's undecided dilemma is inherited whole.