Pectin Rhamnogalacturonan II: On the “Small Stem with Four Branches” in the Primary Cell Walls of Plants

Table 1

Glycosyl residue composition (mol%) and molecular weight (𝑀_𝑤) of rhamnogalacturonan II monomers (mRGs-II) and dimers (dRGs-II) from various plant cell wall pectins.

Sugars (mol%)	Sycamore^a	Arabidopsisthaliana ^b	Sugar Beet^c	Red Beet^d	Red Wine^e	Apple^f	Carrot^f	Tomato^f	Citrus^g
	mRG-II	mRG-II	dRG-II	mRG-II	mRG-II	mRG-II	mRG-II	mRG-II	mRG-II
GalA	31.2	44	37.7	37.4	37.0	33	28.3	35.5	43.3
Rha	12.4	10	11.3	14.2	16.0	17.4	14.3	11.6	16.9
Fuc	2.8–4.0	3	1.6	2.2	3.0	5.5	4.7	4	4.2
Ara	10.0	17	10.9	12.8	11.0	16.8	14	12.4	12.1
Xyl	2.0	3	nd	nd	nd	nd	nd	nd	2.6
Glc	2.0	2	nd	nd	nd	nd	nd	nd	1.3
Gal	9.0	9	12.4	11.8	6.0	6.4	7.8	8.1	10.5
GlcA	3.2	2	7	5.5	5.0	2.8	2.7	4.4	1.5
2-O-Me-Fuc	3.5	1	3.3	3.9	4.0	4.8	5	4.4	0.7
2-O-Me-Xyl	4.8	2	4.9	3.4	3.0	2.9	4	3.3	2.4
Api	6.0–12.2	3	4.5	8.5	6.0	5.4	9.1	7	1.6
AceA	3.5	1	nd	nd	2.0	1.5	3.5	2.3	0.6
KdoA	3.5	3	5.3	ND	4.0	1.1	2.3	4	0.4
DhaA	3.5	ND	5.3	ND	3.0	2.5	4.6	3	ND
Total sugar	99.0–100.4	100	104.2	99.7	100	100.1	100.3	100	98.1
𝑀𝑤 (kDa)	4.5–5.5	ND	9.50–10.5	4.3	4.5–4.7	4.8	4.8	4.8	ND

^a[36, 43, 70]; ^b[36]; ^c[43]; ^d[38]; ^e[44]; ^f[19]; ^g[10, 13].
ND: not determined.
nd: not detected.