Table 1.

Freeze-fracture particles of heterologous proteins

	Density*, μm−2	Diameter†, nm	a/b Ratio	Area‡, nm2	Number of helices§
Opsin	1444  ± 43	(a) 4.4  ± 0.4	1.3	11  ± 2	8  ± 1
		(b) 3.3  ± 0.5
Cx50	1415  ± 81	6.5  ± 0.5	1	34  ± 4	24  ± 3
APQ1	825  ± 63	6.5  ± 0.5	1	33  ± 4	24  ± 3
MIP	3288  ± 136	6.6  ± 0.5	1	34  ± 4	24  ± 3
SGLT1	2070  ± 130	(a) 5.8  ± 0.6	1.2	21  ± 3	15  ± 2
		(b) 4.7  ± 0.5
CFTR	678  ± 27	6.6  ± 0.4	1	34  ± 3	25  ± 2

^*Total density of P face particles. Density of the endogenous P face particles was 355 ± 21/μm². 

^†Diameters were corrected for the thickness of the platinum-carbon film by subtracting 2.4 ± 0.4 nm from the mean diameters obtained from the frequency histograms (see Experimental Procedures). 

^‡Cross-sectional area was obtained by assuming a circular geometry for Cx50, AQP1 and MIP , and CFTR and an elliptical geometry for opsin and SGLT1. 

^§Predicted number of helices was calculated by using 1.40 ± 0.03 nm²/helix (see Fig. 3B). Values are means ± SEM.