1BK7

RIBONUCLEASE MC1 FROM THE SEEDS OF BITTER GOURD

Summary for 1BK7

• Entry DOI: 10.2210/pdb1bk7/pdb
• Descriptor: PROTEIN (RIBONUCLEASE MC1) (2 entities in total)
• Functional Keywords: hydrolase (nucleic acid, rna), hydrolase
• Biological source: Momordica charantia (balsam pear)
• Total number of polymer chains: 1
• Total formula weight: 21227.01

Authors

Nakagawa, A.,Tanaka, I. (deposition date: 1998-07-15, release date: 1999-07-23, Last modification date: 2023-12-27)

Primary citation

Nakagawa, A.,Tanaka, I.,Sakai, R.,Nakashima, T.,Funatsu, G.,Kimura, M.
Crystal structure of a ribonuclease from the seeds of bitter gourd (Momordica charantia) at 1.75 A resolution.
Biochim.Biophys.Acta, 1433:253-260, 1999

PubMed Abstract: The ribonuclease MC1 (RNase MC1) from seeds of bitter gourd (Momordica charantia) consists of 190 amino acid residues with four disulfide bridges and belongs to the RNase T(2) family, including fungal RNases typified by RNase Rh from Rhizopus niveus and RNase T(2) from Aspergillus oryzae. The crystal structure of RNase MC1 has been determined at 1.75 A resolution with an R-factor of 19.7% using the single isomorphous replacement method. RNase MC1 structurally belongs to the (alpha+beta) class of proteins, having ten helices (six alpha-helices and four 3(10)-helices) and eight beta-strands. When the structures of RNase MC1 and RNase Rh are superposed, the close agreement between the alpha-carbon positions for the total structure is obvious: the root mean square deviations calculated only for structurally related 151 alpha-carbon atoms of RNase MC1 and RNase Rh molecules was 1.76 A. Furthermore, the conformation of the catalytic residues His-46, Glu-105, and His-109 in RNase Rh can be easily superposed with that of the possible catalytic residues His-34, Glu-84, and His-88 in RNase MC1. This observation strongly indicates that RNase MC1 from a plant origin catalyzes RNA degradation in a similar manner as fungal RNases.

PubMed: 10446375
DOI: 10.1016/S0167-4838(99)00126-0

Experimental method

X-RAY DIFFRACTION (1.75 Å)