TABLE 1.

Key receptor fragments in photomapping strategy

Protease	Photoadduct massa		Assignment	Ref.
	Glycosylated	Deglycosylated
	kDa
Chymotrypsin	50 (47)	31	L1/part of CR domainb	6
Chymotrypsin	34	23	C-terminal fragmentc	34
Chymotrypsin	20	17	ID-Nd	34
Trypsin	31 (28)	20 (17)	L1e	6

^aMolecular masses in parentheses are exclusive of the respective A- or B-chain adduct.

^bThe fragment contains ∼250-260 residues (supplemental Fig. S2).

^cThe fragment contains (from the C to N terminus) ID-N, Fn2a, and part of Fn1.

^dThe fragment is likely to begin within Fn2a.

^eThe fragment is likely to contain initial residues of the CR domain (supplemental Fig. S1).